3.6-rc1 breaks my laptop graphics (intel)

From: Greg KH
Date: Sun Aug 12 2012 - 14:22:43 EST


Hi Daniel.

The 3.6-rc1 kernel breaks my laptop, booting to a black screen when the
i915 driver initializes itself. I bisected this down to commit
24ded204429fa0f5501d37c63ee35c555c0b75ee (drm/i915: properly enable the
blc controller on the right pipe), and when I revert that, and also
a4f32fc3a37e982fffce8ec583643990ff288419 (drm/i915: don't forget the PCH
backlight registers) which depended on the first patch, my laptop works
just fine.

Below is the combined revert.

Any thoughts? Any patch I can try out?

thanks,

greg k-h

------
Subject: drm/i915: revert 24ded204429fa0f5501d37c63ee35c555c0b75ee and a4f32fc3a37e982fffce8ec583643990ff288419

24ded204429fa0f5501d37c63ee35c555c0b75ee (drm/i915: properly enable the
blc controller on the right pipe) breaks the boot for my laptop, so
revert it, and a4f32fc3a37e982fffce8ec583643990ff288419 (drm/i915: don't
forget the PCH backlight registers) which depended on it.

Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 8435355..4e786f2 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -383,8 +383,7 @@ extern u32 intel_panel_get_max_backlight(struct drm_device *dev);
extern u32 intel_panel_get_backlight(struct drm_device *dev);
extern void intel_panel_set_backlight(struct drm_device *dev, u32 level);
extern int intel_panel_setup_backlight(struct drm_device *dev);
-extern void intel_panel_enable_backlight(struct drm_device *dev,
- enum pipe pipe);
+extern void intel_panel_enable_backlight(struct drm_device *dev);
extern void intel_panel_disable_backlight(struct drm_device *dev);
extern void intel_panel_destroy_backlight(struct drm_device *dev);
extern enum drm_connector_status intel_panel_detect(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index e05c0d3..6547904 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -71,7 +71,6 @@ static struct intel_lvds *intel_attached_lvds(struct drm_connector *connector)
static void intel_lvds_enable(struct intel_lvds *intel_lvds)
{
struct drm_device *dev = intel_lvds->base.base.dev;
- struct intel_crtc *intel_crtc = to_intel_crtc(intel_lvds->base.base.crtc);
struct drm_i915_private *dev_priv = dev->dev_private;
u32 ctl_reg, lvds_reg, stat_reg;

@@ -108,7 +107,7 @@ static void intel_lvds_enable(struct intel_lvds *intel_lvds)
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(dev, intel_crtc->pipe);
+ intel_panel_enable_backlight(dev);
}

static void intel_lvds_disable(struct intel_lvds *intel_lvds)
@@ -1079,14 +1078,35 @@ bool intel_lvds_init(struct drm_device *dev)
goto failed;

out:
- /*
- * Unlock registers and just
- * leave them unlocked
- */
if (HAS_PCH_SPLIT(dev)) {
+ u32 pwm;
+
+ pipe = (I915_READ(PCH_LVDS) & LVDS_PIPEB_SELECT) ? 1 : 0;
+
+ /* make sure PWM is enabled and locked to the LVDS pipe */
+ pwm = I915_READ(BLC_PWM_CPU_CTL2);
+ if (pipe == 0 && (pwm & BLM_PIPE_B))
+ I915_WRITE(BLC_PWM_CPU_CTL2, pwm & ~BLM_PWM_ENABLE);
+ if (pipe)
+ pwm |= BLM_PIPE_B;
+ else
+ pwm &= ~BLM_PIPE_B;
+ I915_WRITE(BLC_PWM_CPU_CTL2, pwm | BLM_PWM_ENABLE);
+
+ pwm = I915_READ(BLC_PWM_PCH_CTL1);
+ pwm |= BLM_PCH_PWM_ENABLE;
+ I915_WRITE(BLC_PWM_PCH_CTL1, pwm);
+ /*
+ * Unlock registers and just
+ * leave them unlocked
+ */
I915_WRITE(PCH_PP_CONTROL,
I915_READ(PCH_PP_CONTROL) | PANEL_UNLOCK_REGS);
} else {
+ /*
+ * Unlock registers and just
+ * leave them unlocked
+ */
I915_WRITE(PP_CONTROL,
I915_READ(PP_CONTROL) | PANEL_UNLOCK_REGS);
}
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 10c7d39..7180cc8 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -287,24 +287,9 @@ void intel_panel_disable_backlight(struct drm_device *dev)

dev_priv->backlight_enabled = false;
intel_panel_actually_set_backlight(dev, 0);
-
- if (INTEL_INFO(dev)->gen >= 4) {
- uint32_t reg, tmp;
-
- reg = HAS_PCH_SPLIT(dev) ? BLC_PWM_CPU_CTL2 : BLC_PWM_CTL2;
-
- I915_WRITE(reg, I915_READ(reg) & ~BLM_PWM_ENABLE);
-
- if (HAS_PCH_SPLIT(dev)) {
- tmp = I915_READ(BLC_PWM_PCH_CTL1);
- tmp &= ~BLM_PCH_PWM_ENABLE;
- I915_WRITE(BLC_PWM_PCH_CTL1, tmp);
- }
- }
}

-void intel_panel_enable_backlight(struct drm_device *dev,
- enum pipe pipe)
+void intel_panel_enable_backlight(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;

@@ -313,40 +298,6 @@ void intel_panel_enable_backlight(struct drm_device *dev,

dev_priv->backlight_enabled = true;
intel_panel_actually_set_backlight(dev, dev_priv->backlight_level);
-
- if (INTEL_INFO(dev)->gen >= 4) {
- uint32_t reg, tmp;
-
- reg = HAS_PCH_SPLIT(dev) ? BLC_PWM_CPU_CTL2 : BLC_PWM_CTL2;
-
-
- tmp = I915_READ(reg);
-
- /* Note that this can also get called through dpms changes. And
- * we don't track the backlight dpms state, hence check whether
- * we have to do anything first. */
- if (tmp & BLM_PWM_ENABLE)
- return;
-
- if (dev_priv->num_pipe == 3)
- tmp &= ~BLM_PIPE_SELECT_IVB;
- else
- tmp &= ~BLM_PIPE_SELECT;
-
- tmp |= BLM_PIPE(pipe);
- tmp &= ~BLM_PWM_ENABLE;
-
- I915_WRITE(reg, tmp);
- POSTING_READ(reg);
- I915_WRITE(reg, tmp | BLM_PWM_ENABLE);
-
- if (HAS_PCH_SPLIT(dev)) {
- tmp = I915_READ(BLC_PWM_PCH_CTL1);
- tmp |= BLM_PCH_PWM_ENABLE;
- tmp &= ~BLM_PCH_OVERRIDE_ENABLE;
- I915_WRITE(BLC_PWM_PCH_CTL1, tmp);
- }
- }
}

static void intel_panel_init_backlight(struct drm_device *dev)
--
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