At Sat, 30 Apr 2011 10:32:04 +0200, Melchior FRANZ wrote:
- Takashi Iwai -- Saturday 30 April 2011:
I remember vaguely that the value zero could be interpreted as the max.
Also, with the patch, does the backlight level can be adjusted correctly to different values? I wonder whether LBPC adjustment really works or not on your machine.
if (!lbpc)lbpc = 0xff; /* max value */This change does *not* work on my machine. The screen stays black again.
Hrm, then it's really hard to say how exactly the system behaves when lbpc=0... I guess we should avoid controlling LBPC in such a case, e.g. something like the patch below (totally untested).
But Intel guys must know of this better... I leave this to their hands.
Yes, backlight adjustment generally works on this notebook, but only with "acpi_osi=Linux" on the command line.
acpi_osi quirk should be better added statically, then.
thanks,
Takashi
--- diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 1c1b27c..c0ab771 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -328,6 +328,7 @@ typedef struct drm_i915_private { struct intel_overlay *overlay;
/* LVDS info */ + int backlight_combination_mode; /* 0=unknown, -1=no, 1=yes */ int backlight_level; /* restore backlight to this value */ bool backlight_enabled; struct drm_display_mode *panel_fixed_mode; diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index a06ff07..320dd5f 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -115,14 +115,24 @@ done: static int is_backlight_combination_mode(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; - - 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; - - return 0; + int combo_mode; + u8 lbpc; + + if (dev_priv->backlight_combination_mode) + return dev_priv->backlight_combination_mode > 0; + + pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc); + if (!lbpc) + combo_mode = 0; + else if (INTEL_INFO(dev)->gen >= 4) + combo_mode = I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE; + else if (IS_GEN2(dev)) + combo_mode = I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE; + else + combo_mode = 0; + + dev_priv->backlight_combination_mode = combo_mode ? -1 : 1; + return combo_mode; }
static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv)