At Fri, 29 Apr 2011 17:58:06 +0200, Melchior FRANZ wrote:
- Linus Torvalds -- Wednesday 27 April 2011:
Go forth and test,
Doesn't work on my notebook with i915/KMS. But then again, neither did 2.6.38 or any of its stable releases. The last working version was 2.6.38-rc8. The problem has been reported[1], but the bug got closed in the wrong assumption that the bug is fixed. I reported that, too. No reactions to that.
The bug was introduced with commit ba3820ade317ee36e496b9b40d2ec3987dd4aef0 by Takashi Iwai. The result is that when using KMS my notebook's[2] screen remains dark, because the backlight isn't turned on.
Reverting commit ba3820ade317ee36e496b9b40d2ec3987dd4aef0 makes my notebook work correctly again as it used to in 2.6.38-rc8 and before.
Could you check whether the patch below changes the behavior? If this cures, it means that the backlight-combo mode doesn't work on your machine.
Takashi
--- diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index a06ff07..bf61e02 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -116,11 +116,13 @@ static int is_backlight_combination_mode(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private;
+#if 0 if (INTEL_INFO(dev)->gen >= 4) return I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE;
if (IS_GEN2(dev)) return I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE; +#endif
return 0; }