Linux 3.14

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

/*
 * Copyright © 2006-2007 Intel Corporation
 * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
 *
 * 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, sublicense,
 * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS 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.
 *
 * Authors:
 *      Eric Anholt <eric@anholt.net>
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */

#include <acpi/button.h>
#include <linux/dmi.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include "intel_drv.h"
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include <linux/acpi.h>

/* Private structure for the integrated LVDS support */
struct intel_lvds_connector {
        struct intel_connector base;

        struct notifier_block lid_notifier;
};

struct intel_lvds_encoder {
        struct intel_encoder base;

        bool is_dual_link;
        u32 reg;

        struct intel_lvds_connector *attached_connector;
};

static struct intel_lvds_encoder *to_lvds_encoder(struct drm_encoder *encoder)
{
        return container_of(encoder, struct intel_lvds_encoder, base.base);
}

static struct intel_lvds_connector *to_lvds_connector(struct drm_connector *connector)
{
        return container_of(connector, struct intel_lvds_connector, base.base);
}

static bool intel_lvds_get_hw_state(struct intel_encoder *encoder,
                                    enum pipe *pipe)
{
        struct drm_device *dev = encoder->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
        u32 tmp;

        tmp = I915_READ(lvds_encoder->reg);

        if (!(tmp & LVDS_PORT_EN))
                return false;

        if (HAS_PCH_CPT(dev))
                *pipe = PORT_TO_PIPE_CPT(tmp);
        else
                *pipe = PORT_TO_PIPE(tmp);

        return true;
}

static void intel_lvds_get_config(struct intel_encoder *encoder,
                                  struct intel_crtc_config *pipe_config)
{
        struct drm_device *dev = encoder->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 lvds_reg, tmp, flags = 0;
        int dotclock;

        if (HAS_PCH_SPLIT(dev))
                lvds_reg = PCH_LVDS;
        else
                lvds_reg = LVDS;

        tmp = I915_READ(lvds_reg);
        if (tmp & LVDS_HSYNC_POLARITY)
                flags |= DRM_MODE_FLAG_NHSYNC;
        else
                flags |= DRM_MODE_FLAG_PHSYNC;
        if (tmp & LVDS_VSYNC_POLARITY)
                flags |= DRM_MODE_FLAG_NVSYNC;
        else
                flags |= DRM_MODE_FLAG_PVSYNC;

        pipe_config->adjusted_mode.flags |= flags;

        /* gen2/3 store dither state in pfit control, needs to match */
        if (INTEL_INFO(dev)->gen < 4) {
                tmp = I915_READ(PFIT_CONTROL);

                pipe_config->gmch_pfit.control |= tmp & PANEL_8TO6_DITHER_ENABLE;
        }

        dotclock = pipe_config->port_clock;

        if (HAS_PCH_SPLIT(dev_priv->dev))
                ironlake_check_encoder_dotclock(pipe_config, dotclock);

        pipe_config->adjusted_mode.crtc_clock = dotclock;
}

/* The LVDS pin pair needs to be on before the DPLLs are enabled.
 * This is an exception to the general rule that mode_set doesn't turn
 * things on.
 */
static void intel_pre_enable_lvds(struct intel_encoder *encoder)
{
        struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
        struct drm_device *dev = encoder->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *crtc = to_intel_crtc(encoder->base.crtc);
        const struct drm_display_mode *adjusted_mode =
                &crtc->config.adjusted_mode;
        int pipe = crtc->pipe;
        u32 temp;

        if (HAS_PCH_SPLIT(dev)) {
                assert_fdi_rx_pll_disabled(dev_priv, pipe);
                assert_shared_dpll_disabled(dev_priv,
                                            intel_crtc_to_shared_dpll(crtc));
        } else {
                assert_pll_disabled(dev_priv, pipe);
        }

        temp = I915_READ(lvds_encoder->reg);
        temp |= LVDS_PORT_EN | LVDS_A0A2_CLKA_POWER_UP;

        if (HAS_PCH_CPT(dev)) {
                temp &= ~PORT_TRANS_SEL_MASK;
                temp |= PORT_TRANS_SEL_CPT(pipe);
        } else {
                if (pipe == 1) {
                        temp |= LVDS_PIPEB_SELECT;
                } else {
                        temp &= ~LVDS_PIPEB_SELECT;
                }
        }

        /* set the corresponsding LVDS_BORDER bit */
        temp &= ~LVDS_BORDER_ENABLE;
        temp |= crtc->config.gmch_pfit.lvds_border_bits;
        /* Set the B0-B3 data pairs corresponding to whether we're going to
         * set the DPLLs for dual-channel mode or not.
         */
        if (lvds_encoder->is_dual_link)
                temp |= LVDS_B0B3_POWER_UP | LVDS_CLKB_POWER_UP;
        else
                temp &= ~(LVDS_B0B3_POWER_UP | LVDS_CLKB_POWER_UP);

        /* It would be nice to set 24 vs 18-bit mode (LVDS_A3_POWER_UP)
         * appropriately here, but we need to look more thoroughly into how
         * panels behave in the two modes.
         */

        /* Set the dithering flag on LVDS as needed, note that there is no
         * special lvds dither control bit on pch-split platforms, dithering is
         * only controlled through the PIPECONF reg. */
        if (INTEL_INFO(dev)->gen == 4) {
                /* Bspec wording suggests that LVDS port dithering only exists
                 * for 18bpp panels. */
                if (crtc->config.dither && crtc->config.pipe_bpp == 18)
                        temp |= LVDS_ENABLE_DITHER;
                else
                        temp &= ~LVDS_ENABLE_DITHER;
        }
        temp &= ~(LVDS_HSYNC_POLARITY | LVDS_VSYNC_POLARITY);
        if (adjusted_mode->flags & DRM_MODE_FLAG_NHSYNC)
                temp |= LVDS_HSYNC_POLARITY;
        if (adjusted_mode->flags & DRM_MODE_FLAG_NVSYNC)
                temp |= LVDS_VSYNC_POLARITY;

        I915_WRITE(lvds_encoder->reg, temp);
}

/**
 * Sets the power state for the panel.
 */
static void intel_enable_lvds(struct intel_encoder *encoder)
{
        struct drm_device *dev = encoder->base.dev;
        struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
        struct intel_connector *intel_connector =
                &lvds_encoder->attached_connector->base;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 ctl_reg, stat_reg;

        if (HAS_PCH_SPLIT(dev)) {
                ctl_reg = PCH_PP_CONTROL;
                stat_reg = PCH_PP_STATUS;
        } else {
                ctl_reg = PP_CONTROL;
                stat_reg = PP_STATUS;
        }

        I915_WRITE(lvds_encoder->reg, I915_READ(lvds_encoder->reg) | LVDS_PORT_EN);

        I915_WRITE(ctl_reg, I915_READ(ctl_reg) | POWER_TARGET_ON);
        POSTING_READ(lvds_encoder->reg);
        if (wait_for((I915_READ(stat_reg) & PP_ON) != 0, 1000))
                DRM_ERROR("timed out waiting for panel to power on\n");

        intel_panel_enable_backlight(intel_connector);
}

static void intel_disable_lvds(struct intel_encoder *encoder)
{
        struct drm_device *dev = encoder->base.dev;
        struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
        struct intel_connector *intel_connector =
                &lvds_encoder->attached_connector->base;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 ctl_reg, stat_reg;

        if (HAS_PCH_SPLIT(dev)) {
                ctl_reg = PCH_PP_CONTROL;
                stat_reg = PCH_PP_STATUS;
        } else {
                ctl_reg = PP_CONTROL;
                stat_reg = PP_STATUS;
        }

        intel_panel_disable_backlight(intel_connector);

        I915_WRITE(ctl_reg, I915_READ(ctl_reg) & ~POWER_TARGET_ON);
        if (wait_for((I915_READ(stat_reg) & PP_ON) == 0, 1000))
                DRM_ERROR("timed out waiting for panel to power off\n");

        I915_WRITE(lvds_encoder->reg, I915_READ(lvds_encoder->reg) & ~LVDS_PORT_EN);
        POSTING_READ(lvds_encoder->reg);
}

static enum drm_mode_status
intel_lvds_mode_valid(struct drm_connector *connector,
                      struct drm_display_mode *mode)
{
        struct intel_connector *intel_connector = to_intel_connector(connector);
        struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;

        if (mode->hdisplay > fixed_mode->hdisplay)
                return MODE_PANEL;
        if (mode->vdisplay > fixed_mode->vdisplay)
                return MODE_PANEL;

        return MODE_OK;
}

static bool intel_lvds_compute_config(struct intel_encoder *intel_encoder,
                                      struct intel_crtc_config *pipe_config)
{
        struct drm_device *dev = intel_encoder->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_lvds_encoder *lvds_encoder =
                to_lvds_encoder(&intel_encoder->base);
        struct intel_connector *intel_connector =
                &lvds_encoder->attached_connector->base;
        struct drm_display_mode *adjusted_mode = &pipe_config->adjusted_mode;
        struct intel_crtc *intel_crtc = lvds_encoder->base.new_crtc;
        unsigned int lvds_bpp;

        /* Should never happen!! */
        if (INTEL_INFO(dev)->gen < 4 && intel_crtc->pipe == 0) {
                DRM_ERROR("Can't support LVDS on pipe A\n");
                return false;
        }

        if ((I915_READ(lvds_encoder->reg) & LVDS_A3_POWER_MASK) ==
            LVDS_A3_POWER_UP)
                lvds_bpp = 8*3;
        else
                lvds_bpp = 6*3;

        if (lvds_bpp != pipe_config->pipe_bpp && !pipe_config->bw_constrained) {
                DRM_DEBUG_KMS("forcing display bpp (was %d) to LVDS (%d)\n",
                              pipe_config->pipe_bpp, lvds_bpp);
                pipe_config->pipe_bpp = lvds_bpp;
        }

        /*
         * We have timings from the BIOS for the panel, put them in
         * to the adjusted mode.  The CRTC will be set up for this mode,
         * with the panel scaling set up to source from the H/VDisplay
         * of the original mode.
         */
        intel_fixed_panel_mode(intel_connector->panel.fixed_mode,
                               adjusted_mode);

        if (HAS_PCH_SPLIT(dev)) {
                pipe_config->has_pch_encoder = true;

                intel_pch_panel_fitting(intel_crtc, pipe_config,
                                        intel_connector->panel.fitting_mode);
        } else {
                intel_gmch_panel_fitting(intel_crtc, pipe_config,
                                         intel_connector->panel.fitting_mode);

        }

        /*
         * XXX: It would be nice to support lower refresh rates on the
         * panels to reduce power consumption, and perhaps match the
         * user's requested refresh rate.
         */

        return true;
}

static void intel_lvds_mode_set(struct intel_encoder *encoder)
{
        /*
         * We don't do anything here, the LVDS port is fully set up in the pre
         * enable hook - the ordering constraints for enabling the lvds port vs.
         * enabling the display pll are too strict.
         */
}

/**
 * Detect the LVDS connection.
 *
 * Since LVDS doesn't have hotlug, we use the lid as a proxy.  Open means
 * connected and closed means disconnected.  We also send hotplug events as
 * needed, using lid status notification from the input layer.
 */
static enum drm_connector_status
intel_lvds_detect(struct drm_connector *connector, bool force)
{
        struct drm_device *dev = connector->dev;
        enum drm_connector_status status;

        DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
                      connector->base.id, drm_get_connector_name(connector));

        status = intel_panel_detect(dev);
        if (status != connector_status_unknown)
                return status;

        return connector_status_connected;
}

/**
 * Return the list of DDC modes if available, or the BIOS fixed mode otherwise.
 */
static int intel_lvds_get_modes(struct drm_connector *connector)
{
        struct intel_lvds_connector *lvds_connector = to_lvds_connector(connector);
        struct drm_device *dev = connector->dev;
        struct drm_display_mode *mode;

        /* use cached edid if we have one */
        if (!IS_ERR_OR_NULL(lvds_connector->base.edid))
                return drm_add_edid_modes(connector, lvds_connector->base.edid);

        mode = drm_mode_duplicate(dev, lvds_connector->base.panel.fixed_mode);
        if (mode == NULL)
                return 0;

        drm_mode_probed_add(connector, mode);
        return 1;
}

static int intel_no_modeset_on_lid_dmi_callback(const struct dmi_system_id *id)
{
        DRM_INFO("Skipping forced modeset for %s\n", id->ident);
        return 1;
}

/* The GPU hangs up on these systems if modeset is performed on LID open */
static const struct dmi_system_id intel_no_modeset_on_lid[] = {
        {
                .callback = intel_no_modeset_on_lid_dmi_callback,
                .ident = "Toshiba Tecra A11",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "TECRA A11"),
                },
        },

        { }     /* terminating entry */
};

/*
 * Lid events. Note the use of 'modeset':
 *  - we set it to MODESET_ON_LID_OPEN on lid close,
 *    and set it to MODESET_DONE on open
 *  - we use it as a "only once" bit (ie we ignore
 *    duplicate events where it was already properly set)
 *  - the suspend/resume paths will set it to
 *    MODESET_SUSPENDED and ignore the lid open event,
 *    because they restore the mode ("lid open").
 */
static int intel_lid_notify(struct notifier_block *nb, unsigned long val,
                            void *unused)
{
        struct intel_lvds_connector *lvds_connector =
                container_of(nb, struct intel_lvds_connector, lid_notifier);
        struct drm_connector *connector = &lvds_connector->base.base;
        struct drm_device *dev = connector->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;

        if (dev->switch_power_state != DRM_SWITCH_POWER_ON)
                return NOTIFY_OK;

        mutex_lock(&dev_priv->modeset_restore_lock);
        if (dev_priv->modeset_restore == MODESET_SUSPENDED)
                goto exit;
        /*
         * check and update the status of LVDS connector after receiving
         * the LID nofication event.
         */
        connector->status = connector->funcs->detect(connector, false);

        /* Don't force modeset on machines where it causes a GPU lockup */
        if (dmi_check_system(intel_no_modeset_on_lid))
                goto exit;
        if (!acpi_lid_open()) {
                /* do modeset on next lid open event */
                dev_priv->modeset_restore = MODESET_ON_LID_OPEN;
                goto exit;
        }

        if (dev_priv->modeset_restore == MODESET_DONE)
                goto exit;

        /*
         * Some old platform's BIOS love to wreak havoc while the lid is closed.
         * We try to detect this here and undo any damage. The split for PCH
         * platforms is rather conservative and a bit arbitrary expect that on
         * those platforms VGA disabling requires actual legacy VGA I/O access,
         * and as part of the cleanup in the hw state restore we also redisable
         * the vga plane.
         */
        if (!HAS_PCH_SPLIT(dev)) {
                drm_modeset_lock_all(dev);
                intel_modeset_setup_hw_state(dev, true);
                drm_modeset_unlock_all(dev);
        }

        dev_priv->modeset_restore = MODESET_DONE;

exit:
        mutex_unlock(&dev_priv->modeset_restore_lock);
        return NOTIFY_OK;
}

/**
 * intel_lvds_destroy - unregister and free LVDS structures
 * @connector: connector to free
 *
 * Unregister the DDC bus for this connector then free the driver private
 * structure.
 */
static void intel_lvds_destroy(struct drm_connector *connector)
{
        struct intel_lvds_connector *lvds_connector =
                to_lvds_connector(connector);

        if (lvds_connector->lid_notifier.notifier_call)
                acpi_lid_notifier_unregister(&lvds_connector->lid_notifier);

        if (!IS_ERR_OR_NULL(lvds_connector->base.edid))
                kfree(lvds_connector->base.edid);

        intel_panel_fini(&lvds_connector->base.panel);

        drm_connector_cleanup(connector);
        kfree(connector);
}

static int intel_lvds_set_property(struct drm_connector *connector,
                                   struct drm_property *property,
                                   uint64_t value)
{
        struct intel_connector *intel_connector = to_intel_connector(connector);
        struct drm_device *dev = connector->dev;

        if (property == dev->mode_config.scaling_mode_property) {
                struct drm_crtc *crtc;

                if (value == DRM_MODE_SCALE_NONE) {
                        DRM_DEBUG_KMS("no scaling not supported\n");
                        return -EINVAL;
                }

                if (intel_connector->panel.fitting_mode == value) {
                        /* the LVDS scaling property is not changed */
                        return 0;
                }
                intel_connector->panel.fitting_mode = value;

                crtc = intel_attached_encoder(connector)->base.crtc;
                if (crtc && crtc->enabled) {
                        /*
                         * If the CRTC is enabled, the display will be changed
                         * according to the new panel fitting mode.
                         */
                        intel_crtc_restore_mode(crtc);
                }
        }

        return 0;
}

static const struct drm_connector_helper_funcs intel_lvds_connector_helper_funcs = {
        .get_modes = intel_lvds_get_modes,
        .mode_valid = intel_lvds_mode_valid,
        .best_encoder = intel_best_encoder,
};

static const struct drm_connector_funcs intel_lvds_connector_funcs = {
        .dpms = intel_connector_dpms,
        .detect = intel_lvds_detect,
        .fill_modes = drm_helper_probe_single_connector_modes,
        .set_property = intel_lvds_set_property,
        .destroy = intel_lvds_destroy,
};

static const struct drm_encoder_funcs intel_lvds_enc_funcs = {
        .destroy = intel_encoder_destroy,
};

static int __init intel_no_lvds_dmi_callback(const struct dmi_system_id *id)
{
        DRM_INFO("Skipping LVDS initialization for %s\n", id->ident);
        return 1;
}

/* These systems claim to have LVDS, but really don't */
static const struct dmi_system_id intel_no_lvds[] = {
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Apple Mac Mini (Core series)",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Apple"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Macmini1,1"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Apple Mac Mini (Core 2 series)",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Apple"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Macmini2,1"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "MSI IM-945GSE-A",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "MSI"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "A9830IMS"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Dell Studio Hybrid",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Studio Hybrid 140g"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Dell OptiPlex FX170",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex FX170"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "AOpen Mini PC",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "AOpen"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "i965GMx-IF"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "AOpen Mini PC MP915",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "AOpen"),
                        DMI_MATCH(DMI_BOARD_NAME, "i915GMx-F"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "AOpen i915GMm-HFS",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "AOpen"),
                        DMI_MATCH(DMI_BOARD_NAME, "i915GMm-HFS"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "AOpen i45GMx-I",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "AOpen"),
                        DMI_MATCH(DMI_BOARD_NAME, "i45GMx-I"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Aopen i945GTt-VFA",
                .matches = {
                        DMI_MATCH(DMI_PRODUCT_VERSION, "AO00001JW"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Clientron U800",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Clientron"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "U800"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Clientron E830",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Clientron"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "E830"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Asus EeeBox PC EB1007",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "EB1007"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Asus AT5NM10T-I",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                        DMI_MATCH(DMI_BOARD_NAME, "AT5NM10T-I"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Hewlett-Packard HP t5740",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
                        DMI_MATCH(DMI_PRODUCT_NAME, " t5740"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Hewlett-Packard t5745",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "hp t5745"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Hewlett-Packard st5747",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "Hewlett-Packard"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "hp st5747"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "MSI Wind Box DC500",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "MICRO-STAR INTERNATIONAL CO., LTD"),
                        DMI_MATCH(DMI_BOARD_NAME, "MS-7469"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Gigabyte GA-D525TUD",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "Gigabyte Technology Co., Ltd."),
                        DMI_MATCH(DMI_BOARD_NAME, "D525TUD"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Supermicro X7SPA-H",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Supermicro"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "X7SPA-H"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Fujitsu Esprimo Q900",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Q900"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Intel D410PT",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "Intel"),
                        DMI_MATCH(DMI_BOARD_NAME, "D410PT"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Intel D425KT",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "Intel"),
                        DMI_EXACT_MATCH(DMI_BOARD_NAME, "D425KT"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Intel D510MO",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "Intel"),
                        DMI_EXACT_MATCH(DMI_BOARD_NAME, "D510MO"),
                },
        },
        {
                .callback = intel_no_lvds_dmi_callback,
                .ident = "Intel D525MW",
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "Intel"),
                        DMI_EXACT_MATCH(DMI_BOARD_NAME, "D525MW"),
                },
        },

        { }     /* terminating entry */
};

/*
 * Enumerate the child dev array parsed from VBT to check whether
 * the LVDS is present.
 * If it is present, return 1.
 * If it is not present, return false.
 * If no child dev is parsed from VBT, it assumes that the LVDS is present.
 */
static bool lvds_is_present_in_vbt(struct drm_device *dev,
                                   u8 *i2c_pin)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        int i;

        if (!dev_priv->vbt.child_dev_num)
                return true;

        for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
                union child_device_config *uchild = dev_priv->vbt.child_dev + i;
                struct old_child_dev_config *child = &uchild->old;

                /* If the device type is not LFP, continue.
                 * We have to check both the new identifiers as well as the
                 * old for compatibility with some BIOSes.
                 */
                if (child->device_type != DEVICE_TYPE_INT_LFP &&
                    child->device_type != DEVICE_TYPE_LFP)
                        continue;

                if (intel_gmbus_is_port_valid(child->i2c_pin))
                        *i2c_pin = child->i2c_pin;

                /* However, we cannot trust the BIOS writers to populate
                 * the VBT correctly.  Since LVDS requires additional
                 * information from AIM blocks, a non-zero addin offset is
                 * a good indicator that the LVDS is actually present.
                 */
                if (child->addin_offset)
                        return true;

                /* But even then some BIOS writers perform some black magic
                 * and instantiate the device without reference to any
                 * additional data.  Trust that if the VBT was written into
                 * the OpRegion then they have validated the LVDS's existence.
                 */
                if (dev_priv->opregion.vbt)
                        return true;
        }

        return false;
}

static int intel_dual_link_lvds_callback(const struct dmi_system_id *id)
{
        DRM_INFO("Forcing lvds to dual link mode on %s\n", id->ident);
        return 1;
}

static const struct dmi_system_id intel_dual_link_lvds[] = {
        {
                .callback = intel_dual_link_lvds_callback,
                .ident = "Apple MacBook Pro (Core i5/i7 Series)",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
                        DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro8,2"),
                },
        },
        { }     /* terminating entry */
};

bool intel_is_dual_link_lvds(struct drm_device *dev)
{
        struct intel_encoder *encoder;
        struct intel_lvds_encoder *lvds_encoder;

        list_for_each_entry(encoder, &dev->mode_config.encoder_list,
                            base.head) {
                if (encoder->type == INTEL_OUTPUT_LVDS) {
                        lvds_encoder = to_lvds_encoder(&encoder->base);

                        return lvds_encoder->is_dual_link;
                }
        }

        return false;
}

static bool compute_is_dual_link_lvds(struct intel_lvds_encoder *lvds_encoder)
{
        struct drm_device *dev = lvds_encoder->base.base.dev;
        unsigned int val;
        struct drm_i915_private *dev_priv = dev->dev_private;

        /* use the module option value if specified */
        if (i915_lvds_channel_mode > 0)
                return i915_lvds_channel_mode == 2;

        if (dmi_check_system(intel_dual_link_lvds))
                return true;

        /* BIOS should set the proper LVDS register value at boot, but
         * in reality, it doesn't set the value when the lid is closed;
         * we need to check "the value to be set" in VBT when LVDS
         * register is uninitialized.
         */
        val = I915_READ(lvds_encoder->reg);
        if (!(val & ~(LVDS_PIPE_MASK | LVDS_DETECTED)))
                val = dev_priv->vbt.bios_lvds_val;

        return (val & LVDS_CLKB_POWER_MASK) == LVDS_CLKB_POWER_UP;
}

static bool intel_lvds_supported(struct drm_device *dev)
{
        /* With the introduction of the PCH we gained a dedicated
         * LVDS presence pin, use it. */
        if (HAS_PCH_IBX(dev) || HAS_PCH_CPT(dev))
                return true;

        /* Otherwise LVDS was only attached to mobile products,
         * except for the inglorious 830gm */
        if (INTEL_INFO(dev)->gen <= 4 && IS_MOBILE(dev) && !IS_I830(dev))
                return true;

        return false;
}

/**
 * intel_lvds_init - setup LVDS connectors on this device
 * @dev: drm device
 *
 * Create the connector, register the LVDS DDC bus, and try to figure out what
 * modes we can display on the LVDS panel (if present).
 */
void intel_lvds_init(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_lvds_encoder *lvds_encoder;
        struct intel_encoder *intel_encoder;
        struct intel_lvds_connector *lvds_connector;
        struct intel_connector *intel_connector;
        struct drm_connector *connector;
        struct drm_encoder *encoder;
        struct drm_display_mode *scan; /* *modes, *bios_mode; */
        struct drm_display_mode *fixed_mode = NULL;
        struct edid *edid;
        struct drm_crtc *crtc;
        u32 lvds;
        int pipe;
        u8 pin;

        if (!intel_lvds_supported(dev))
                return;

        /* Skip init on machines we know falsely report LVDS */
        if (dmi_check_system(intel_no_lvds))
                return;

        pin = GMBUS_PORT_PANEL;
        if (!lvds_is_present_in_vbt(dev, &pin)) {
                DRM_DEBUG_KMS("LVDS is not present in VBT\n");
                return;
        }

        if (HAS_PCH_SPLIT(dev)) {
                if ((I915_READ(PCH_LVDS) & LVDS_DETECTED) == 0)
                        return;
                if (dev_priv->vbt.edp_support) {
                        DRM_DEBUG_KMS("disable LVDS for eDP support\n");
                        return;
                }
        }

        lvds_encoder = kzalloc(sizeof(*lvds_encoder), GFP_KERNEL);
        if (!lvds_encoder)
                return;

        lvds_connector = kzalloc(sizeof(*lvds_connector), GFP_KERNEL);
        if (!lvds_connector) {
                kfree(lvds_encoder);
                return;
        }

        lvds_encoder->attached_connector = lvds_connector;

        intel_encoder = &lvds_encoder->base;
        encoder = &intel_encoder->base;
        intel_connector = &lvds_connector->base;
        connector = &intel_connector->base;
        drm_connector_init(dev, &intel_connector->base, &intel_lvds_connector_funcs,
                           DRM_MODE_CONNECTOR_LVDS);

        drm_encoder_init(dev, &intel_encoder->base, &intel_lvds_enc_funcs,
                         DRM_MODE_ENCODER_LVDS);

        intel_encoder->enable = intel_enable_lvds;
        intel_encoder->pre_enable = intel_pre_enable_lvds;
        intel_encoder->compute_config = intel_lvds_compute_config;
        intel_encoder->mode_set = intel_lvds_mode_set;
        intel_encoder->disable = intel_disable_lvds;
        intel_encoder->get_hw_state = intel_lvds_get_hw_state;
        intel_encoder->get_config = intel_lvds_get_config;
        intel_connector->get_hw_state = intel_connector_get_hw_state;

        intel_connector_attach_encoder(intel_connector, intel_encoder);
        intel_encoder->type = INTEL_OUTPUT_LVDS;

        intel_encoder->cloneable = false;
        if (HAS_PCH_SPLIT(dev))
                intel_encoder->crtc_mask = (1 << 0) | (1 << 1) | (1 << 2);
        else if (IS_GEN4(dev))
                intel_encoder->crtc_mask = (1 << 0) | (1 << 1);
        else
                intel_encoder->crtc_mask = (1 << 1);

        drm_connector_helper_add(connector, &intel_lvds_connector_helper_funcs);
        connector->display_info.subpixel_order = SubPixelHorizontalRGB;
        connector->interlace_allowed = false;
        connector->doublescan_allowed = false;

        if (HAS_PCH_SPLIT(dev)) {
                lvds_encoder->reg = PCH_LVDS;
        } else {
                lvds_encoder->reg = LVDS;
        }

        /* create the scaling mode property */
        drm_mode_create_scaling_mode_property(dev);
        drm_object_attach_property(&connector->base,
                                      dev->mode_config.scaling_mode_property,
                                      DRM_MODE_SCALE_ASPECT);
        intel_connector->panel.fitting_mode = DRM_MODE_SCALE_ASPECT;
        /*
         * LVDS discovery:
         * 1) check for EDID on DDC
         * 2) check for VBT data
         * 3) check to see if LVDS is already on
         *    if none of the above, no panel
         * 4) make sure lid is open
         *    if closed, act like it's not there for now
         */

        /*
         * Attempt to get the fixed panel mode from DDC.  Assume that the
         * preferred mode is the right one.
         */
        edid = drm_get_edid(connector, intel_gmbus_get_adapter(dev_priv, pin));
        if (edid) {
                if (drm_add_edid_modes(connector, edid)) {
                        drm_mode_connector_update_edid_property(connector,
                                                                edid);
                } else {
                        kfree(edid);
                        edid = ERR_PTR(-EINVAL);
                }
        } else {
                edid = ERR_PTR(-ENOENT);
        }
        lvds_connector->base.edid = edid;

        if (IS_ERR_OR_NULL(edid)) {
                /* Didn't get an EDID, so
                 * Set wide sync ranges so we get all modes
                 * handed to valid_mode for checking
                 */
                connector->display_info.min_vfreq = 0;
                connector->display_info.max_vfreq = 200;
                connector->display_info.min_hfreq = 0;
                connector->display_info.max_hfreq = 200;
        }

        list_for_each_entry(scan, &connector->probed_modes, head) {
                if (scan->type & DRM_MODE_TYPE_PREFERRED) {
                        DRM_DEBUG_KMS("using preferred mode from EDID: ");
                        drm_mode_debug_printmodeline(scan);

                        fixed_mode = drm_mode_duplicate(dev, scan);
                        if (fixed_mode) {
                                intel_connector->panel.downclock_mode =
                                        intel_find_panel_downclock(dev,
                                        fixed_mode, connector);
                                if (intel_connector->panel.downclock_mode !=
                                        NULL && i915_lvds_downclock) {
                                        /* We found the downclock for LVDS. */
                                        dev_priv->lvds_downclock_avail = true;
                                        dev_priv->lvds_downclock =
                                                intel_connector->panel.
                                                downclock_mode->clock;
                                        DRM_DEBUG_KMS("LVDS downclock is found"
                                        " in EDID. Normal clock %dKhz, "
                                        "downclock %dKhz\n",
                                        fixed_mode->clock,
                                        dev_priv->lvds_downclock);
                                }
                                goto out;
                        }
                }
        }

        /* Failed to get EDID, what about VBT? */
        if (dev_priv->vbt.lfp_lvds_vbt_mode) {
                DRM_DEBUG_KMS("using mode from VBT: ");
                drm_mode_debug_printmodeline(dev_priv->vbt.lfp_lvds_vbt_mode);

                fixed_mode = drm_mode_duplicate(dev, dev_priv->vbt.lfp_lvds_vbt_mode);
                if (fixed_mode) {
                        fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
                        goto out;
                }
        }

        /*
         * If we didn't get EDID, try checking if the panel is already turned
         * on.  If so, assume that whatever is currently programmed is the
         * correct mode.
         */

        /* Ironlake: FIXME if still fail, not try pipe mode now */
        if (HAS_PCH_SPLIT(dev))
                goto failed;

        lvds = I915_READ(LVDS);
        pipe = (lvds & LVDS_PIPEB_SELECT) ? 1 : 0;
        crtc = intel_get_crtc_for_pipe(dev, pipe);

        if (crtc && (lvds & LVDS_PORT_EN)) {
                fixed_mode = intel_crtc_mode_get(dev, crtc);
                if (fixed_mode) {
                        DRM_DEBUG_KMS("using current (BIOS) mode: ");
                        drm_mode_debug_printmodeline(fixed_mode);
                        fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
                        goto out;
                }
        }

        /* If we still don't have a mode after all that, give up. */
        if (!fixed_mode)
                goto failed;

out:
        lvds_encoder->is_dual_link = compute_is_dual_link_lvds(lvds_encoder);
        DRM_DEBUG_KMS("detected %s-link lvds configuration\n",
                      lvds_encoder->is_dual_link ? "dual" : "single");

        /*
         * Unlock registers and just
         * leave them unlocked
         */
        if (HAS_PCH_SPLIT(dev)) {
                I915_WRITE(PCH_PP_CONTROL,
                           I915_READ(PCH_PP_CONTROL) | PANEL_UNLOCK_REGS);
        } else {
                I915_WRITE(PP_CONTROL,
                           I915_READ(PP_CONTROL) | PANEL_UNLOCK_REGS);
        }
        lvds_connector->lid_notifier.notifier_call = intel_lid_notify;
        if (acpi_lid_notifier_register(&lvds_connector->lid_notifier)) {
                DRM_DEBUG_KMS("lid notifier registration failed\n");
                lvds_connector->lid_notifier.notifier_call = NULL;
        }
        drm_sysfs_connector_add(connector);

        intel_panel_init(&intel_connector->panel, fixed_mode);
        intel_panel_setup_backlight(connector);

        return;

failed:
        DRM_DEBUG_KMS("No LVDS modes found, disabling.\n");
        drm_connector_cleanup(connector);
        drm_encoder_cleanup(encoder);
        if (fixed_mode)
                drm_mode_destroy(dev, fixed_mode);
        kfree(lvds_encoder);
        kfree(lvds_connector);
        return;
}