Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm...

[deliverable/linux.git] / drivers / gpu / drm / i915 / i915_drv.c

/* i915_drv.c -- i830,i845,i855,i865,i915 driver -*- linux-c -*-
 */
/*
 *
 * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include <linux/device.h>
#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_trace.h"
#include "intel_drv.h"

#include <linux/console.h>
#include <linux/module.h>
#include <drm/drm_crtc_helper.h>

static int i915_modeset __read_mostly = -1;
module_param_named(modeset, i915_modeset, int, 0400);
MODULE_PARM_DESC(modeset,
                "Use kernel modesetting [KMS] (0=DRM_I915_KMS from .config, "
                "1=on, -1=force vga console preference [default])");

unsigned int i915_fbpercrtc __always_unused = 0;
module_param_named(fbpercrtc, i915_fbpercrtc, int, 0400);

int i915_panel_ignore_lid __read_mostly = 1;
module_param_named(panel_ignore_lid, i915_panel_ignore_lid, int, 0600);
MODULE_PARM_DESC(panel_ignore_lid,
                "Override lid status (0=autodetect, 1=autodetect disabled [default], "
                "-1=force lid closed, -2=force lid open)");

unsigned int i915_powersave __read_mostly = 1;
module_param_named(powersave, i915_powersave, int, 0600);
MODULE_PARM_DESC(powersave,
                "Enable powersavings, fbc, downclocking, etc. (default: true)");

int i915_semaphores __read_mostly = -1;
module_param_named(semaphores, i915_semaphores, int, 0600);
MODULE_PARM_DESC(semaphores,
                "Use semaphores for inter-ring sync (default: -1 (use per-chip defaults))");

int i915_enable_rc6 __read_mostly = -1;
module_param_named(i915_enable_rc6, i915_enable_rc6, int, 0400);
MODULE_PARM_DESC(i915_enable_rc6,
                "Enable power-saving render C-state 6. "
                "Different stages can be selected via bitmask values "
                "(0 = disable; 1 = enable rc6; 2 = enable deep rc6; 4 = enable deepest rc6). "
                "For example, 3 would enable rc6 and deep rc6, and 7 would enable everything. "
                "default: -1 (use per-chip default)");

int i915_enable_fbc __read_mostly = -1;
module_param_named(i915_enable_fbc, i915_enable_fbc, int, 0600);
MODULE_PARM_DESC(i915_enable_fbc,
                "Enable frame buffer compression for power savings "
                "(default: -1 (use per-chip default))");

unsigned int i915_lvds_downclock __read_mostly = 0;
module_param_named(lvds_downclock, i915_lvds_downclock, int, 0400);
MODULE_PARM_DESC(lvds_downclock,
                "Use panel (LVDS/eDP) downclocking for power savings "
                "(default: false)");

int i915_lvds_channel_mode __read_mostly;
module_param_named(lvds_channel_mode, i915_lvds_channel_mode, int, 0600);
MODULE_PARM_DESC(lvds_channel_mode,
                 "Specify LVDS channel mode "
                 "(0=probe BIOS [default], 1=single-channel, 2=dual-channel)");

int i915_panel_use_ssc __read_mostly = -1;
module_param_named(lvds_use_ssc, i915_panel_use_ssc, int, 0600);
MODULE_PARM_DESC(lvds_use_ssc,
                "Use Spread Spectrum Clock with panels [LVDS/eDP] "
                "(default: auto from VBT)");

int i915_vbt_sdvo_panel_type __read_mostly = -1;
module_param_named(vbt_sdvo_panel_type, i915_vbt_sdvo_panel_type, int, 0600);
MODULE_PARM_DESC(vbt_sdvo_panel_type,
                "Override/Ignore selection of SDVO panel mode in the VBT "
                "(-2=ignore, -1=auto [default], index in VBT BIOS table)");

static bool i915_try_reset __read_mostly = true;
module_param_named(reset, i915_try_reset, bool, 0600);
MODULE_PARM_DESC(reset, "Attempt GPU resets (default: true)");

bool i915_enable_hangcheck __read_mostly = true;
module_param_named(enable_hangcheck, i915_enable_hangcheck, bool, 0644);
MODULE_PARM_DESC(enable_hangcheck,
                "Periodically check GPU activity for detecting hangs. "
                "WARNING: Disabling this can cause system wide hangs. "
                "(default: true)");

int i915_enable_ppgtt __read_mostly = -1;
module_param_named(i915_enable_ppgtt, i915_enable_ppgtt, int, 0600);
MODULE_PARM_DESC(i915_enable_ppgtt,
                "Enable PPGTT (default: true)");

unsigned int i915_preliminary_hw_support __read_mostly = 0;
module_param_named(preliminary_hw_support, i915_preliminary_hw_support, int, 0600);
MODULE_PARM_DESC(preliminary_hw_support,
                "Enable preliminary hardware support. "
                "Enable Haswell and ValleyView Support. "
                "(default: false)");

static struct drm_driver driver;
extern int intel_agp_enabled;

#define INTEL_VGA_DEVICE(id, info) {            \
        .class = PCI_BASE_CLASS_DISPLAY << 16,  \
        .class_mask = 0xff0000,                 \
        .vendor = 0x8086,                       \
        .device = id,                           \
        .subvendor = PCI_ANY_ID,                \
        .subdevice = PCI_ANY_ID,                \
        .driver_data = (unsigned long) info }

static const struct intel_device_info intel_i830_info = {
        .gen = 2, .is_mobile = 1, .cursor_needs_physical = 1,
        .has_overlay = 1, .overlay_needs_physical = 1,
};

static const struct intel_device_info intel_845g_info = {
        .gen = 2,
        .has_overlay = 1, .overlay_needs_physical = 1,
};

static const struct intel_device_info intel_i85x_info = {
        .gen = 2, .is_i85x = 1, .is_mobile = 1,
        .cursor_needs_physical = 1,
        .has_overlay = 1, .overlay_needs_physical = 1,
};

static const struct intel_device_info intel_i865g_info = {
        .gen = 2,
        .has_overlay = 1, .overlay_needs_physical = 1,
};

static const struct intel_device_info intel_i915g_info = {
        .gen = 3, .is_i915g = 1, .cursor_needs_physical = 1,
        .has_overlay = 1, .overlay_needs_physical = 1,
};
static const struct intel_device_info intel_i915gm_info = {
        .gen = 3, .is_mobile = 1,
        .cursor_needs_physical = 1,
        .has_overlay = 1, .overlay_needs_physical = 1,
        .supports_tv = 1,
};
static const struct intel_device_info intel_i945g_info = {
        .gen = 3, .has_hotplug = 1, .cursor_needs_physical = 1,
        .has_overlay = 1, .overlay_needs_physical = 1,
};
static const struct intel_device_info intel_i945gm_info = {
        .gen = 3, .is_i945gm = 1, .is_mobile = 1,
        .has_hotplug = 1, .cursor_needs_physical = 1,
        .has_overlay = 1, .overlay_needs_physical = 1,
        .supports_tv = 1,
};

static const struct intel_device_info intel_i965g_info = {
        .gen = 4, .is_broadwater = 1,
        .has_hotplug = 1,
        .has_overlay = 1,
};

static const struct intel_device_info intel_i965gm_info = {
        .gen = 4, .is_crestline = 1,
        .is_mobile = 1, .has_fbc = 1, .has_hotplug = 1,
        .has_overlay = 1,
        .supports_tv = 1,
};

static const struct intel_device_info intel_g33_info = {
        .gen = 3, .is_g33 = 1,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_overlay = 1,
};

static const struct intel_device_info intel_g45_info = {
        .gen = 4, .is_g4x = 1, .need_gfx_hws = 1,
        .has_pipe_cxsr = 1, .has_hotplug = 1,
        .has_bsd_ring = 1,
};

static const struct intel_device_info intel_gm45_info = {
        .gen = 4, .is_g4x = 1,
        .is_mobile = 1, .need_gfx_hws = 1, .has_fbc = 1,
        .has_pipe_cxsr = 1, .has_hotplug = 1,
        .supports_tv = 1,
        .has_bsd_ring = 1,
};

static const struct intel_device_info intel_pineview_info = {
        .gen = 3, .is_g33 = 1, .is_pineview = 1, .is_mobile = 1,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_overlay = 1,
};

static const struct intel_device_info intel_ironlake_d_info = {
        .gen = 5,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_bsd_ring = 1,
};

static const struct intel_device_info intel_ironlake_m_info = {
        .gen = 5, .is_mobile = 1,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_fbc = 1,
        .has_bsd_ring = 1,
};

static const struct intel_device_info intel_sandybridge_d_info = {
        .gen = 6,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_bsd_ring = 1,
        .has_blt_ring = 1,
        .has_llc = 1,
        .has_force_wake = 1,
};

static const struct intel_device_info intel_sandybridge_m_info = {
        .gen = 6, .is_mobile = 1,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_fbc = 1,
        .has_bsd_ring = 1,
        .has_blt_ring = 1,
        .has_llc = 1,
        .has_force_wake = 1,
};

static const struct intel_device_info intel_ivybridge_d_info = {
        .is_ivybridge = 1, .gen = 7,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_bsd_ring = 1,
        .has_blt_ring = 1,
        .has_llc = 1,
        .has_force_wake = 1,
};

static const struct intel_device_info intel_ivybridge_m_info = {
        .is_ivybridge = 1, .gen = 7, .is_mobile = 1,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_fbc = 0,   /* FBC is not enabled on Ivybridge mobile yet */
        .has_bsd_ring = 1,
        .has_blt_ring = 1,
        .has_llc = 1,
        .has_force_wake = 1,
};

static const struct intel_device_info intel_valleyview_m_info = {
        .gen = 7, .is_mobile = 1,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_fbc = 0,
        .has_bsd_ring = 1,
        .has_blt_ring = 1,
        .is_valleyview = 1,
        .display_mmio_offset = VLV_DISPLAY_BASE,
};

static const struct intel_device_info intel_valleyview_d_info = {
        .gen = 7,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_fbc = 0,
        .has_bsd_ring = 1,
        .has_blt_ring = 1,
        .is_valleyview = 1,
        .display_mmio_offset = VLV_DISPLAY_BASE,
};

static const struct intel_device_info intel_haswell_d_info = {
        .is_haswell = 1, .gen = 7,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_bsd_ring = 1,
        .has_blt_ring = 1,
        .has_llc = 1,
        .has_force_wake = 1,
};

static const struct intel_device_info intel_haswell_m_info = {
        .is_haswell = 1, .gen = 7, .is_mobile = 1,
        .need_gfx_hws = 1, .has_hotplug = 1,
        .has_bsd_ring = 1,
        .has_blt_ring = 1,
        .has_llc = 1,
        .has_force_wake = 1,
};

static const struct pci_device_id pciidlist[] = {               /* aka */
        INTEL_VGA_DEVICE(0x3577, &intel_i830_info),             /* I830_M */
        INTEL_VGA_DEVICE(0x2562, &intel_845g_info),             /* 845_G */
        INTEL_VGA_DEVICE(0x3582, &intel_i85x_info),             /* I855_GM */
        INTEL_VGA_DEVICE(0x358e, &intel_i85x_info),
        INTEL_VGA_DEVICE(0x2572, &intel_i865g_info),            /* I865_G */
        INTEL_VGA_DEVICE(0x2582, &intel_i915g_info),            /* I915_G */
        INTEL_VGA_DEVICE(0x258a, &intel_i915g_info),            /* E7221_G */
        INTEL_VGA_DEVICE(0x2592, &intel_i915gm_info),           /* I915_GM */
        INTEL_VGA_DEVICE(0x2772, &intel_i945g_info),            /* I945_G */
        INTEL_VGA_DEVICE(0x27a2, &intel_i945gm_info),           /* I945_GM */
        INTEL_VGA_DEVICE(0x27ae, &intel_i945gm_info),           /* I945_GME */
        INTEL_VGA_DEVICE(0x2972, &intel_i965g_info),            /* I946_GZ */
        INTEL_VGA_DEVICE(0x2982, &intel_i965g_info),            /* G35_G */
        INTEL_VGA_DEVICE(0x2992, &intel_i965g_info),            /* I965_Q */
        INTEL_VGA_DEVICE(0x29a2, &intel_i965g_info),            /* I965_G */
        INTEL_VGA_DEVICE(0x29b2, &intel_g33_info),              /* Q35_G */
        INTEL_VGA_DEVICE(0x29c2, &intel_g33_info),              /* G33_G */
        INTEL_VGA_DEVICE(0x29d2, &intel_g33_info),              /* Q33_G */
        INTEL_VGA_DEVICE(0x2a02, &intel_i965gm_info),           /* I965_GM */
        INTEL_VGA_DEVICE(0x2a12, &intel_i965gm_info),           /* I965_GME */
        INTEL_VGA_DEVICE(0x2a42, &intel_gm45_info),             /* GM45_G */
        INTEL_VGA_DEVICE(0x2e02, &intel_g45_info),              /* IGD_E_G */
        INTEL_VGA_DEVICE(0x2e12, &intel_g45_info),              /* Q45_G */
        INTEL_VGA_DEVICE(0x2e22, &intel_g45_info),              /* G45_G */
        INTEL_VGA_DEVICE(0x2e32, &intel_g45_info),              /* G41_G */
        INTEL_VGA_DEVICE(0x2e42, &intel_g45_info),              /* B43_G */
        INTEL_VGA_DEVICE(0x2e92, &intel_g45_info),              /* B43_G.1 */
        INTEL_VGA_DEVICE(0xa001, &intel_pineview_info),
        INTEL_VGA_DEVICE(0xa011, &intel_pineview_info),
        INTEL_VGA_DEVICE(0x0042, &intel_ironlake_d_info),
        INTEL_VGA_DEVICE(0x0046, &intel_ironlake_m_info),
        INTEL_VGA_DEVICE(0x0102, &intel_sandybridge_d_info),
        INTEL_VGA_DEVICE(0x0112, &intel_sandybridge_d_info),
        INTEL_VGA_DEVICE(0x0122, &intel_sandybridge_d_info),
        INTEL_VGA_DEVICE(0x0106, &intel_sandybridge_m_info),
        INTEL_VGA_DEVICE(0x0116, &intel_sandybridge_m_info),
        INTEL_VGA_DEVICE(0x0126, &intel_sandybridge_m_info),
        INTEL_VGA_DEVICE(0x010A, &intel_sandybridge_d_info),
        INTEL_VGA_DEVICE(0x0156, &intel_ivybridge_m_info), /* GT1 mobile */
        INTEL_VGA_DEVICE(0x0166, &intel_ivybridge_m_info), /* GT2 mobile */
        INTEL_VGA_DEVICE(0x0152, &intel_ivybridge_d_info), /* GT1 desktop */
        INTEL_VGA_DEVICE(0x0162, &intel_ivybridge_d_info), /* GT2 desktop */
        INTEL_VGA_DEVICE(0x015a, &intel_ivybridge_d_info), /* GT1 server */
        INTEL_VGA_DEVICE(0x016a, &intel_ivybridge_d_info), /* GT2 server */
        INTEL_VGA_DEVICE(0x0402, &intel_haswell_d_info), /* GT1 desktop */
        INTEL_VGA_DEVICE(0x0412, &intel_haswell_d_info), /* GT2 desktop */
        INTEL_VGA_DEVICE(0x0422, &intel_haswell_d_info), /* GT2 desktop */
        INTEL_VGA_DEVICE(0x040a, &intel_haswell_d_info), /* GT1 server */
        INTEL_VGA_DEVICE(0x041a, &intel_haswell_d_info), /* GT2 server */
        INTEL_VGA_DEVICE(0x042a, &intel_haswell_d_info), /* GT2 server */
        INTEL_VGA_DEVICE(0x0406, &intel_haswell_m_info), /* GT1 mobile */
        INTEL_VGA_DEVICE(0x0416, &intel_haswell_m_info), /* GT2 mobile */
        INTEL_VGA_DEVICE(0x0426, &intel_haswell_m_info), /* GT2 mobile */
        INTEL_VGA_DEVICE(0x0C02, &intel_haswell_d_info), /* SDV GT1 desktop */
        INTEL_VGA_DEVICE(0x0C12, &intel_haswell_d_info), /* SDV GT2 desktop */
        INTEL_VGA_DEVICE(0x0C22, &intel_haswell_d_info), /* SDV GT2 desktop */
        INTEL_VGA_DEVICE(0x0C0A, &intel_haswell_d_info), /* SDV GT1 server */
        INTEL_VGA_DEVICE(0x0C1A, &intel_haswell_d_info), /* SDV GT2 server */
        INTEL_VGA_DEVICE(0x0C2A, &intel_haswell_d_info), /* SDV GT2 server */
        INTEL_VGA_DEVICE(0x0C06, &intel_haswell_m_info), /* SDV GT1 mobile */
        INTEL_VGA_DEVICE(0x0C16, &intel_haswell_m_info), /* SDV GT2 mobile */
        INTEL_VGA_DEVICE(0x0C26, &intel_haswell_m_info), /* SDV GT2 mobile */
        INTEL_VGA_DEVICE(0x0A02, &intel_haswell_d_info), /* ULT GT1 desktop */
        INTEL_VGA_DEVICE(0x0A12, &intel_haswell_d_info), /* ULT GT2 desktop */
        INTEL_VGA_DEVICE(0x0A22, &intel_haswell_d_info), /* ULT GT2 desktop */
        INTEL_VGA_DEVICE(0x0A0A, &intel_haswell_d_info), /* ULT GT1 server */
        INTEL_VGA_DEVICE(0x0A1A, &intel_haswell_d_info), /* ULT GT2 server */
        INTEL_VGA_DEVICE(0x0A2A, &intel_haswell_d_info), /* ULT GT2 server */
        INTEL_VGA_DEVICE(0x0A06, &intel_haswell_m_info), /* ULT GT1 mobile */
        INTEL_VGA_DEVICE(0x0A16, &intel_haswell_m_info), /* ULT GT2 mobile */
        INTEL_VGA_DEVICE(0x0A26, &intel_haswell_m_info), /* ULT GT2 mobile */
        INTEL_VGA_DEVICE(0x0D02, &intel_haswell_d_info), /* CRW GT1 desktop */
        INTEL_VGA_DEVICE(0x0D12, &intel_haswell_d_info), /* CRW GT2 desktop */
        INTEL_VGA_DEVICE(0x0D22, &intel_haswell_d_info), /* CRW GT2 desktop */
        INTEL_VGA_DEVICE(0x0D0A, &intel_haswell_d_info), /* CRW GT1 server */
        INTEL_VGA_DEVICE(0x0D1A, &intel_haswell_d_info), /* CRW GT2 server */
        INTEL_VGA_DEVICE(0x0D2A, &intel_haswell_d_info), /* CRW GT2 server */
        INTEL_VGA_DEVICE(0x0D06, &intel_haswell_m_info), /* CRW GT1 mobile */
        INTEL_VGA_DEVICE(0x0D16, &intel_haswell_m_info), /* CRW GT2 mobile */
        INTEL_VGA_DEVICE(0x0D26, &intel_haswell_m_info), /* CRW GT2 mobile */
        INTEL_VGA_DEVICE(0x0f30, &intel_valleyview_m_info),
        INTEL_VGA_DEVICE(0x0157, &intel_valleyview_m_info),
        INTEL_VGA_DEVICE(0x0155, &intel_valleyview_d_info),
        {0, 0, 0}
};

#if defined(CONFIG_DRM_I915_KMS)
MODULE_DEVICE_TABLE(pci, pciidlist);
#endif

void intel_detect_pch(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct pci_dev *pch;

        /*
         * The reason to probe ISA bridge instead of Dev31:Fun0 is to
         * make graphics device passthrough work easy for VMM, that only
         * need to expose ISA bridge to let driver know the real hardware
         * underneath. This is a requirement from virtualization team.
         */
        pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
        if (pch) {
                if (pch->vendor == PCI_VENDOR_ID_INTEL) {
                        unsigned short id;
                        id = pch->device & INTEL_PCH_DEVICE_ID_MASK;
                        dev_priv->pch_id = id;

                        if (id == INTEL_PCH_IBX_DEVICE_ID_TYPE) {
                                dev_priv->pch_type = PCH_IBX;
                                dev_priv->num_pch_pll = 2;
                                DRM_DEBUG_KMS("Found Ibex Peak PCH\n");
                                WARN_ON(!IS_GEN5(dev));
                        } else if (id == INTEL_PCH_CPT_DEVICE_ID_TYPE) {
                                dev_priv->pch_type = PCH_CPT;
                                dev_priv->num_pch_pll = 2;
                                DRM_DEBUG_KMS("Found CougarPoint PCH\n");
                                WARN_ON(!(IS_GEN6(dev) || IS_IVYBRIDGE(dev)));
                        } else if (id == INTEL_PCH_PPT_DEVICE_ID_TYPE) {
                                /* PantherPoint is CPT compatible */
                                dev_priv->pch_type = PCH_CPT;
                                dev_priv->num_pch_pll = 2;
                                DRM_DEBUG_KMS("Found PatherPoint PCH\n");
                                WARN_ON(!(IS_GEN6(dev) || IS_IVYBRIDGE(dev)));
                        } else if (id == INTEL_PCH_LPT_DEVICE_ID_TYPE) {
                                dev_priv->pch_type = PCH_LPT;
                                dev_priv->num_pch_pll = 0;
                                DRM_DEBUG_KMS("Found LynxPoint PCH\n");
                                WARN_ON(!IS_HASWELL(dev));
                        } else if (id == INTEL_PCH_LPT_LP_DEVICE_ID_TYPE) {
                                dev_priv->pch_type = PCH_LPT;
                                dev_priv->num_pch_pll = 0;
                                DRM_DEBUG_KMS("Found LynxPoint LP PCH\n");
                                WARN_ON(!IS_HASWELL(dev));
                        }
                        BUG_ON(dev_priv->num_pch_pll > I915_NUM_PLLS);
                }
                pci_dev_put(pch);
        }
}

bool i915_semaphore_is_enabled(struct drm_device *dev)
{
        if (INTEL_INFO(dev)->gen < 6)
                return 0;

        if (i915_semaphores >= 0)
                return i915_semaphores;

#ifdef CONFIG_INTEL_IOMMU
        /* Enable semaphores on SNB when IO remapping is off */
        if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped)
                return false;
#endif

        return 1;
}

static int i915_drm_freeze(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        /* ignore lid events during suspend */
        mutex_lock(&dev_priv->modeset_restore_lock);
        dev_priv->modeset_restore = MODESET_SUSPENDED;
        mutex_unlock(&dev_priv->modeset_restore_lock);

        intel_set_power_well(dev, true);

        drm_kms_helper_poll_disable(dev);

        pci_save_state(dev->pdev);

        /* If KMS is active, we do the leavevt stuff here */
        if (drm_core_check_feature(dev, DRIVER_MODESET)) {
                int error = i915_gem_idle(dev);
                if (error) {
                        dev_err(&dev->pdev->dev,
                                "GEM idle failed, resume might fail\n");
                        return error;
                }

                cancel_delayed_work_sync(&dev_priv->rps.delayed_resume_work);

                intel_modeset_disable(dev);

                drm_irq_uninstall(dev);
                dev_priv->enable_hotplug_processing = false;
        }

        i915_save_state(dev);

        intel_opregion_fini(dev);

        console_lock();
        intel_fbdev_set_suspend(dev, 1);
        console_unlock();

        return 0;
}

int i915_suspend(struct drm_device *dev, pm_message_t state)
{
        int error;

        if (!dev || !dev->dev_private) {
                DRM_ERROR("dev: %p\n", dev);
                DRM_ERROR("DRM not initialized, aborting suspend.\n");
                return -ENODEV;
        }

        if (state.event == PM_EVENT_PRETHAW)
                return 0;


        if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
                return 0;

        error = i915_drm_freeze(dev);
        if (error)
                return error;

        if (state.event == PM_EVENT_SUSPEND) {
                /* Shut down the device */
                pci_disable_device(dev->pdev);
                pci_set_power_state(dev->pdev, PCI_D3hot);
        }

        return 0;
}

void intel_console_resume(struct work_struct *work)
{
        struct drm_i915_private *dev_priv =
                container_of(work, struct drm_i915_private,
                             console_resume_work);
        struct drm_device *dev = dev_priv->dev;

        console_lock();
        intel_fbdev_set_suspend(dev, 0);
        console_unlock();
}

static int __i915_drm_thaw(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        int error = 0;

        i915_restore_state(dev);
        intel_opregion_setup(dev);

        /* KMS EnterVT equivalent */
        if (drm_core_check_feature(dev, DRIVER_MODESET)) {
                intel_init_pch_refclk(dev);

                mutex_lock(&dev->struct_mutex);
                dev_priv->mm.suspended = 0;

                error = i915_gem_init_hw(dev);
                mutex_unlock(&dev->struct_mutex);

                /* We need working interrupts for modeset enabling ... */
                drm_irq_install(dev);

                intel_modeset_init_hw(dev);
                intel_modeset_setup_hw_state(dev, false);

                /*
                 * ... but also need to make sure that hotplug processing
                 * doesn't cause havoc. Like in the driver load code we don't
                 * bother with the tiny race here where we might loose hotplug
                 * notifications.
                 * */
                intel_hpd_init(dev);
                dev_priv->enable_hotplug_processing = true;
        }

        intel_opregion_init(dev);

        /*
         * The console lock can be pretty contented on resume due
         * to all the printk activity.  Try to keep it out of the hot
         * path of resume if possible.
         */
        if (console_trylock()) {
                intel_fbdev_set_suspend(dev, 0);
                console_unlock();
        } else {
                schedule_work(&dev_priv->console_resume_work);
        }

        mutex_lock(&dev_priv->modeset_restore_lock);
        dev_priv->modeset_restore = MODESET_DONE;
        mutex_unlock(&dev_priv->modeset_restore_lock);
        return error;
}

static int i915_drm_thaw(struct drm_device *dev)
{
        int error = 0;

        intel_gt_reset(dev);

        if (drm_core_check_feature(dev, DRIVER_MODESET)) {
                mutex_lock(&dev->struct_mutex);
                i915_gem_restore_gtt_mappings(dev);
                mutex_unlock(&dev->struct_mutex);
        }

        __i915_drm_thaw(dev);

        return error;
}

int i915_resume(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        int ret;

        if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
                return 0;

        if (pci_enable_device(dev->pdev))
                return -EIO;

        pci_set_master(dev->pdev);

        intel_gt_reset(dev);

        /*
         * Platforms with opregion should have sane BIOS, older ones (gen3 and
         * earlier) need this since the BIOS might clear all our scratch PTEs.
         */
        if (drm_core_check_feature(dev, DRIVER_MODESET) &&
            !dev_priv->opregion.header) {
                mutex_lock(&dev->struct_mutex);
                i915_gem_restore_gtt_mappings(dev);
                mutex_unlock(&dev->struct_mutex);
        }

        ret = __i915_drm_thaw(dev);
        if (ret)
                return ret;

        drm_kms_helper_poll_enable(dev);
        return 0;
}

static int i8xx_do_reset(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

        if (IS_I85X(dev))
                return -ENODEV;

        I915_WRITE(D_STATE, I915_READ(D_STATE) | DSTATE_GFX_RESET_I830);
        POSTING_READ(D_STATE);

        if (IS_I830(dev) || IS_845G(dev)) {
                I915_WRITE(DEBUG_RESET_I830,
                           DEBUG_RESET_DISPLAY |
                           DEBUG_RESET_RENDER |
                           DEBUG_RESET_FULL);
                POSTING_READ(DEBUG_RESET_I830);
                msleep(1);

                I915_WRITE(DEBUG_RESET_I830, 0);
                POSTING_READ(DEBUG_RESET_I830);
        }

        msleep(1);

        I915_WRITE(D_STATE, I915_READ(D_STATE) & ~DSTATE_GFX_RESET_I830);
        POSTING_READ(D_STATE);

        return 0;
}

static int i965_reset_complete(struct drm_device *dev)
{
        u8 gdrst;
        pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);
        return (gdrst & GRDOM_RESET_ENABLE) == 0;
}

static int i965_do_reset(struct drm_device *dev)
{
        int ret;
        u8 gdrst;

        /*
         * Set the domains we want to reset (GRDOM/bits 2 and 3) as
         * well as the reset bit (GR/bit 0).  Setting the GR bit
         * triggers the reset; when done, the hardware will clear it.
         */
        pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);
        pci_write_config_byte(dev->pdev, I965_GDRST,
                              gdrst | GRDOM_RENDER |
                              GRDOM_RESET_ENABLE);
        ret =  wait_for(i965_reset_complete(dev), 500);
        if (ret)
                return ret;

        /* We can't reset render&media without also resetting display ... */
        pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);
        pci_write_config_byte(dev->pdev, I965_GDRST,
                              gdrst | GRDOM_MEDIA |
                              GRDOM_RESET_ENABLE);

        return wait_for(i965_reset_complete(dev), 500);
}

static int ironlake_do_reset(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 gdrst;
        int ret;

        gdrst = I915_READ(MCHBAR_MIRROR_BASE + ILK_GDSR);
        I915_WRITE(MCHBAR_MIRROR_BASE + ILK_GDSR,
                   gdrst | GRDOM_RENDER | GRDOM_RESET_ENABLE);
        ret = wait_for(I915_READ(MCHBAR_MIRROR_BASE + ILK_GDSR) & 0x1, 500);
        if (ret)
                return ret;

        /* We can't reset render&media without also resetting display ... */
        gdrst = I915_READ(MCHBAR_MIRROR_BASE + ILK_GDSR);
        I915_WRITE(MCHBAR_MIRROR_BASE + ILK_GDSR,
                   gdrst | GRDOM_MEDIA | GRDOM_RESET_ENABLE);
        return wait_for(I915_READ(MCHBAR_MIRROR_BASE + ILK_GDSR) & 0x1, 500);
}

static int gen6_do_reset(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        int     ret;
        unsigned long irqflags;

        /* Hold gt_lock across reset to prevent any register access
         * with forcewake not set correctly
         */
        spin_lock_irqsave(&dev_priv->gt_lock, irqflags);

        /* Reset the chip */

        /* GEN6_GDRST is not in the gt power well, no need to check
         * for fifo space for the write or forcewake the chip for
         * the read
         */
        I915_WRITE_NOTRACE(GEN6_GDRST, GEN6_GRDOM_FULL);

        /* Spin waiting for the device to ack the reset request */
        ret = wait_for((I915_READ_NOTRACE(GEN6_GDRST) & GEN6_GRDOM_FULL) == 0, 500);

        /* If reset with a user forcewake, try to restore, otherwise turn it off */
        if (dev_priv->forcewake_count)
                dev_priv->gt.force_wake_get(dev_priv);
        else
                dev_priv->gt.force_wake_put(dev_priv);

        /* Restore fifo count */
        dev_priv->gt_fifo_count = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES);

        spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags);
        return ret;
}

int intel_gpu_reset(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        int ret = -ENODEV;

        switch (INTEL_INFO(dev)->gen) {
        case 7:
        case 6:
                ret = gen6_do_reset(dev);
                break;
        case 5:
                ret = ironlake_do_reset(dev);
                break;
        case 4:
                ret = i965_do_reset(dev);
                break;
        case 2:
                ret = i8xx_do_reset(dev);
                break;
        }

        /* Also reset the gpu hangman. */
        if (dev_priv->gpu_error.stop_rings) {
                DRM_DEBUG("Simulated gpu hang, resetting stop_rings\n");
                dev_priv->gpu_error.stop_rings = 0;
                if (ret == -ENODEV) {
                        DRM_ERROR("Reset not implemented, but ignoring "
                                  "error for simulated gpu hangs\n");
                        ret = 0;
                }
        }

        return ret;
}

/**
 * i915_reset - reset chip after a hang
 * @dev: drm device to reset
 *
 * Reset the chip.  Useful if a hang is detected. Returns zero on successful
 * reset or otherwise an error code.
 *
 * Procedure is fairly simple:
 *   - reset the chip using the reset reg
 *   - re-init context state
 *   - re-init hardware status page
 *   - re-init ring buffer
 *   - re-init interrupt state
 *   - re-init display
 */
int i915_reset(struct drm_device *dev)
{
        drm_i915_private_t *dev_priv = dev->dev_private;
        int ret;

        if (!i915_try_reset)
                return 0;

        mutex_lock(&dev->struct_mutex);

        i915_gem_reset(dev);

        ret = -ENODEV;
        if (get_seconds() - dev_priv->gpu_error.last_reset < 5)
                DRM_ERROR("GPU hanging too fast, declaring wedged!\n");
        else
                ret = intel_gpu_reset(dev);

        dev_priv->gpu_error.last_reset = get_seconds();
        if (ret) {
                DRM_ERROR("Failed to reset chip.\n");
                mutex_unlock(&dev->struct_mutex);
                return ret;
        }

        /* Ok, now get things going again... */

        /*
         * Everything depends on having the GTT running, so we need to start
         * there.  Fortunately we don't need to do this unless we reset the
         * chip at a PCI level.
         *
         * Next we need to restore the context, but we don't use those
         * yet either...
         *
         * Ring buffer needs to be re-initialized in the KMS case, or if X
         * was running at the time of the reset (i.e. we weren't VT
         * switched away).
         */
        if (drm_core_check_feature(dev, DRIVER_MODESET) ||
                        !dev_priv->mm.suspended) {
                struct intel_ring_buffer *ring;
                int i;

                dev_priv->mm.suspended = 0;

                i915_gem_init_swizzling(dev);

                for_each_ring(ring, dev_priv, i)
                        ring->init(ring);

                i915_gem_context_init(dev);
                i915_gem_init_ppgtt(dev);

                /*
                 * It would make sense to re-init all the other hw state, at
                 * least the rps/rc6/emon init done within modeset_init_hw. For
                 * some unknown reason, this blows up my ilk, so don't.
                 */

                mutex_unlock(&dev->struct_mutex);

                drm_irq_uninstall(dev);
                drm_irq_install(dev);
                intel_hpd_init(dev);
        } else {
                mutex_unlock(&dev->struct_mutex);
        }

        return 0;
}

static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
        struct intel_device_info *intel_info =
                (struct intel_device_info *) ent->driver_data;

        if (intel_info->is_valleyview)
                if(!i915_preliminary_hw_support) {
                        DRM_ERROR("Preliminary hardware support disabled\n");
                        return -ENODEV;
                }

        /* Only bind to function 0 of the device. Early generations
         * used function 1 as a placeholder for multi-head. This causes
         * us confusion instead, especially on the systems where both
         * functions have the same PCI-ID!
         */
        if (PCI_FUNC(pdev->devfn))
                return -ENODEV;

        /* We've managed to ship a kms-enabled ddx that shipped with an XvMC
         * implementation for gen3 (and only gen3) that used legacy drm maps
         * (gasp!) to share buffers between X and the client. Hence we need to
         * keep around the fake agp stuff for gen3, even when kms is enabled. */
        if (intel_info->gen != 3) {
                driver.driver_features &=
                        ~(DRIVER_USE_AGP | DRIVER_REQUIRE_AGP);
        } else if (!intel_agp_enabled) {
                DRM_ERROR("drm/i915 can't work without intel_agp module!\n");
                return -ENODEV;
        }

        return drm_get_pci_dev(pdev, ent, &driver);
}

static void
i915_pci_remove(struct pci_dev *pdev)
{
        struct drm_device *dev = pci_get_drvdata(pdev);

        drm_put_dev(dev);
}

static int i915_pm_suspend(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct drm_device *drm_dev = pci_get_drvdata(pdev);
        int error;

        if (!drm_dev || !drm_dev->dev_private) {
                dev_err(dev, "DRM not initialized, aborting suspend.\n");
                return -ENODEV;
        }

        if (drm_dev->switch_power_state == DRM_SWITCH_POWER_OFF)
                return 0;

        error = i915_drm_freeze(drm_dev);
        if (error)
                return error;

        pci_disable_device(pdev);
        pci_set_power_state(pdev, PCI_D3hot);

        return 0;
}

static int i915_pm_resume(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct drm_device *drm_dev = pci_get_drvdata(pdev);

        return i915_resume(drm_dev);
}

static int i915_pm_freeze(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct drm_device *drm_dev = pci_get_drvdata(pdev);

        if (!drm_dev || !drm_dev->dev_private) {
                dev_err(dev, "DRM not initialized, aborting suspend.\n");
                return -ENODEV;
        }

        return i915_drm_freeze(drm_dev);
}

static int i915_pm_thaw(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct drm_device *drm_dev = pci_get_drvdata(pdev);

        return i915_drm_thaw(drm_dev);
}

static int i915_pm_poweroff(struct device *dev)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct drm_device *drm_dev = pci_get_drvdata(pdev);

        return i915_drm_freeze(drm_dev);
}

static const struct dev_pm_ops i915_pm_ops = {
        .suspend = i915_pm_suspend,
        .resume = i915_pm_resume,
        .freeze = i915_pm_freeze,
        .thaw = i915_pm_thaw,
        .poweroff = i915_pm_poweroff,
        .restore = i915_pm_resume,
};

static const struct vm_operations_struct i915_gem_vm_ops = {
        .fault = i915_gem_fault,
        .open = drm_gem_vm_open,
        .close = drm_gem_vm_close,
};

static const struct file_operations i915_driver_fops = {
        .owner = THIS_MODULE,
        .open = drm_open,
        .release = drm_release,
        .unlocked_ioctl = drm_ioctl,
        .mmap = drm_gem_mmap,
        .poll = drm_poll,
        .fasync = drm_fasync,
        .read = drm_read,
#ifdef CONFIG_COMPAT
        .compat_ioctl = i915_compat_ioctl,
#endif
        .llseek = noop_llseek,
};

static struct drm_driver driver = {
        /* Don't use MTRRs here; the Xserver or userspace app should
         * deal with them for Intel hardware.
         */
        .driver_features =
            DRIVER_USE_AGP | DRIVER_REQUIRE_AGP | /* DRIVER_USE_MTRR |*/
            DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_GEM | DRIVER_PRIME,
        .load = i915_driver_load,
        .unload = i915_driver_unload,
        .open = i915_driver_open,
        .lastclose = i915_driver_lastclose,
        .preclose = i915_driver_preclose,
        .postclose = i915_driver_postclose,

        /* Used in place of i915_pm_ops for non-DRIVER_MODESET */
        .suspend = i915_suspend,
        .resume = i915_resume,

        .device_is_agp = i915_driver_device_is_agp,
        .master_create = i915_master_create,
        .master_destroy = i915_master_destroy,
#if defined(CONFIG_DEBUG_FS)
        .debugfs_init = i915_debugfs_init,
        .debugfs_cleanup = i915_debugfs_cleanup,
#endif
        .gem_init_object = i915_gem_init_object,
        .gem_free_object = i915_gem_free_object,
        .gem_vm_ops = &i915_gem_vm_ops,

        .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
        .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
        .gem_prime_export = i915_gem_prime_export,
        .gem_prime_import = i915_gem_prime_import,

        .dumb_create = i915_gem_dumb_create,
        .dumb_map_offset = i915_gem_mmap_gtt,
        .dumb_destroy = i915_gem_dumb_destroy,
        .ioctls = i915_ioctls,
        .fops = &i915_driver_fops,
        .name = DRIVER_NAME,
        .desc = DRIVER_DESC,
        .date = DRIVER_DATE,
        .major = DRIVER_MAJOR,
        .minor = DRIVER_MINOR,
        .patchlevel = DRIVER_PATCHLEVEL,
};

static struct pci_driver i915_pci_driver = {
        .name = DRIVER_NAME,
        .id_table = pciidlist,
        .probe = i915_pci_probe,
        .remove = i915_pci_remove,
        .driver.pm = &i915_pm_ops,
};

static int __init i915_init(void)
{
        driver.num_ioctls = i915_max_ioctl;

        /*
         * If CONFIG_DRM_I915_KMS is set, default to KMS unless
         * explicitly disabled with the module pararmeter.
         *
         * Otherwise, just follow the parameter (defaulting to off).
         *
         * Allow optional vga_text_mode_force boot option to override
         * the default behavior.
         */
#if defined(CONFIG_DRM_I915_KMS)
        if (i915_modeset != 0)
                driver.driver_features |= DRIVER_MODESET;
#endif
        if (i915_modeset == 1)
                driver.driver_features |= DRIVER_MODESET;

#ifdef CONFIG_VGA_CONSOLE
        if (vgacon_text_force() && i915_modeset == -1)
                driver.driver_features &= ~DRIVER_MODESET;
#endif

        if (!(driver.driver_features & DRIVER_MODESET))
                driver.get_vblank_timestamp = NULL;

        return drm_pci_init(&driver, &i915_pci_driver);
}

static void __exit i915_exit(void)
{
        drm_pci_exit(&driver, &i915_pci_driver);
}

module_init(i915_init);
module_exit(i915_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL and additional rights");

/* We give fast paths for the really cool registers */
#define NEEDS_FORCE_WAKE(dev_priv, reg) \
        ((HAS_FORCE_WAKE((dev_priv)->dev)) && \
         ((reg) < 0x40000) &&            \
         ((reg) != FORCEWAKE))
static void
ilk_dummy_write(struct drm_i915_private *dev_priv)
{
        /* WaIssueDummyWriteToWakeupFromRC6: Issue a dummy write to wake up the
         * chip from rc6 before touching it for real. MI_MODE is masked, hence
         * harmless to write 0 into. */
        I915_WRITE_NOTRACE(MI_MODE, 0);
}

#define __i915_read(x, y) \
u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
        u##x val = 0; \
        if (IS_GEN5(dev_priv->dev)) \
                ilk_dummy_write(dev_priv); \
        if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
                unsigned long irqflags; \
                spin_lock_irqsave(&dev_priv->gt_lock, irqflags); \
                if (dev_priv->forcewake_count == 0) \
                        dev_priv->gt.force_wake_get(dev_priv); \
                val = read##y(dev_priv->regs + reg); \
                if (dev_priv->forcewake_count == 0) \
                        dev_priv->gt.force_wake_put(dev_priv); \
                spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); \
        } else { \
                val = read##y(dev_priv->regs + reg); \
        } \
        trace_i915_reg_rw(false, reg, val, sizeof(val)); \
        return val; \
}

__i915_read(8, b)
__i915_read(16, w)
__i915_read(32, l)
__i915_read(64, q)
#undef __i915_read

#define __i915_write(x, y) \
void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
        u32 __fifo_ret = 0; \
        trace_i915_reg_rw(true, reg, val, sizeof(val)); \
        if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
                __fifo_ret = __gen6_gt_wait_for_fifo(dev_priv); \
        } \
        if (IS_GEN5(dev_priv->dev)) \
                ilk_dummy_write(dev_priv); \
        if (IS_HASWELL(dev_priv->dev) && (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) { \
                DRM_ERROR("Unknown unclaimed register before writing to %x\n", reg); \
                I915_WRITE_NOTRACE(GEN7_ERR_INT, ERR_INT_MMIO_UNCLAIMED); \
        } \
        write##y(val, dev_priv->regs + reg); \
        if (unlikely(__fifo_ret)) { \
                gen6_gt_check_fifodbg(dev_priv); \
        } \
        if (IS_HASWELL(dev_priv->dev) && (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) { \
                DRM_ERROR("Unclaimed write to %x\n", reg); \
                writel(ERR_INT_MMIO_UNCLAIMED, dev_priv->regs + GEN7_ERR_INT);  \
        } \
}
__i915_write(8, b)
__i915_write(16, w)
__i915_write(32, l)
__i915_write(64, q)
#undef __i915_write

static const struct register_whitelist {
        uint64_t offset;
        uint32_t size;
        uint32_t gen_bitmask; /* support gens, 0x10 for 4, 0x30 for 4 and 5, etc. */
} whitelist[] = {
        { RING_TIMESTAMP(RENDER_RING_BASE), 8, 0xF0 },
};

int i915_reg_read_ioctl(struct drm_device *dev,
                        void *data, struct drm_file *file)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_i915_reg_read *reg = data;
        struct register_whitelist const *entry = whitelist;
        int i;

        for (i = 0; i < ARRAY_SIZE(whitelist); i++, entry++) {
                if (entry->offset == reg->offset &&
                    (1 << INTEL_INFO(dev)->gen & entry->gen_bitmask))
                        break;
        }

        if (i == ARRAY_SIZE(whitelist))
                return -EINVAL;

        switch (entry->size) {
        case 8:
                reg->val = I915_READ64(reg->offset);
                break;
        case 4:
                reg->val = I915_READ(reg->offset);
                break;
        case 2:
                reg->val = I915_READ16(reg->offset);
                break;
        case 1:
                reg->val = I915_READ8(reg->offset);
                break;
        default:
                WARN_ON(1);
                return -EINVAL;
        }

        return 0;
}