drm/i915: Preserve VGACNTR bits from the BIOS

My Fujistsu-Siemens Lifebook S6010 doesn't like to resume from
S3 unless VGACNTR has been restore to the original value. The BIOS
value in this case was 0x0124008E. Setting the "VGA disable" bit
doesn't interfere with the S3 resume fortunately.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Thomas Richter <richter@rus.uni-stuttgart.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index dbf9a26d1a89b8180f76a402d7ae8a12c855c7a2..36f3da6096e40dbed5ab98591973879f45d57e68 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1676,6 +1676,8 @@ struct drm_i915_private {
         */
        struct workqueue_struct *dp_wq;
 
+       uint32_t bios_vgacntr;
+
        /* Old dri1 support infrastructure, beware the dragons ya fools entering
         * here! */
        struct i915_dri1_state dri1;

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 7e20b00d56a3cd5e26465f63a6910431b85c2587..0fe99bf18344ea5a9145942ab090a7698a0cc685 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -12727,7 +12727,11 @@ static void i915_disable_vga(struct drm_device *dev)
        vga_put(dev->pdev, VGA_RSRC_LEGACY_IO);
        udelay(300);
 
-       I915_WRITE(vga_reg, VGA_DISP_DISABLE);
+       /*
+        * Fujitsu-Siemens Lifebook S6010 (830) has problems resuming
+        * from S3 without preserving (some of?) the other bits.
+        */
+       I915_WRITE(vga_reg, dev_priv->bios_vgacntr | VGA_DISP_DISABLE);
        POSTING_READ(vga_reg);
 }
 
@@ -12816,6 +12820,8 @@ void intel_modeset_init(struct drm_device *dev)
 
        intel_shared_dpll_init(dev);
 
+       /* save the BIOS value before clobbering it */
+       dev_priv->bios_vgacntr = I915_READ(i915_vgacntrl_reg(dev));
        /* Just disable it once at startup */
        i915_disable_vga(dev);
        intel_setup_outputs(dev);