Add Cc. Michael Chang for he is our i915 expert.
Hi Melchior,
於 日，2011-05-08 於 16:05 +0200，Melchior FRANZ 提到：
Does it work to you direct control brightness by access by /sys/class/backlight/acer-wmi/brightness ?
No. A number written to this virtual file is accepted and remembered, but it doesn't actually change the brightness. It takes setpci to do that.
I thought the video driver still is the KEY component for backlight issues, need fix the problem in video driver first.
As I remember, use setpci to control brightness is not recommended because BIOS or ACPI will also touch brightness level. That will be better control brightness by the function that was provided by BIOS. e.g. ACPI or WMI interface, or direct control by EC.
Well, sounds plausible. And I wouldn't do it if it weren't the only way at the moment. :-)
That means that will be better fix your Fn key control brightness like before, you just need press Fn key to change brightness and don't need have any workaround.
OK. I have added a lot of debug messages to intel_panel.c yesterday. All it told me was that it seems to work correctly wiht acpi_osi=Linux. Except that it doesn't actually change the brightness. Without acpi_osi the functions aren't called at all and none of my messages showed up.
I traced _Q event in your DSDT, when acpi_osi=Linux, it run the Intel OpRegion logic for change brightness. And, finally, intel_opregion will access the function the were provided by intel_panel. So, the problem still back to intel_panel.
After discuss with Michael chang, we thought there have problem in your brightness level after add combination mode:
vi driver/gpu/drm/i915/intel_panel.c
void intel_panel_set_backlight(struct drm_device *dev, u32 level) { struct drm_i915_private *dev_priv = dev->dev_private; u32 tmp;
DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level);
if (HAS_PCH_SPLIT(dev)) return intel_pch_panel_set_backlight(dev, level);
if (is_backlight_combination_mode(dev)){ u32 max = intel_panel_get_max_backlight(dev); u8 lbpc;
lbpc = level * 0xfe / max + 1; level /= lbpc; /* maybe the level changed by lbpc */ pci_write_config_byte(dev->pdev, PCI_LBPC, lbpc); }
tmp = I915_READ(BLC_PWM_CTL); if (IS_PINEVIEW(dev)) { tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1); level <<= 1; } else tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK; I915_WRITE(BLC_PWM_CTL, tmp | level); }
We need to know some run time value when intel_panel_set_backlight call by funciton key. Please help to apply the attached debug patch to intel_panel.c then attached dmesg.
Looks like current status is we try to fix bko#31522 but the patch causes your brightness no work by press Fn key even with acpi_osi=Linux. Does it right?
The history is: with acpi_osi=Linux everything worked with 2.6.38-rc8. With 2.6.38 the screen stayed black. The patch that only ignored lbpc=0 worked (IIRC) including key adjustment. Later patches broke keys.
replace acpi_osi=Linux by acpi_osi="!Windows 2006"
Does it also works to you for backlight control?
No, doesn't work.
We can test the acpi_osi="!Windows 2006" again after we fix the i915's problem.
Thank's Joey Lee
The following is debug patch, and please add kernel parameter drm.debug=0x02 :
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index f8f86e5..f62dbd9 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -236,17 +236,22 @@ void intel_panel_set_backlight(struct drm_device *dev, u32 level) u32 max = intel_panel_get_max_backlight(dev); u8 lbpc;
+ DRM_DEBUG_DRIVER("set backlight max = % lbpc = level * 0xfe / max + 1; + DRM_DEBUG_DRIVER("set backlight lbpc = %d\n", lbpc); level /= lbpc; pci_write_config_byte(dev->pdev, PCI_LBPC, lbpc); }
tmp = I915_READ(BLC_PWM_CTL); + DRM_DEBUG_DRIVER("set backlight tmp(1) = %d\n", tmp); if (IS_PINEVIEW(dev)) { tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1); level <<= 1; } else tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK; + DRM_DEBUG_DRIVER("set backlight tmp(2) = %d\n", tmp); + DRM_DEBUG_DRIVER("set backlight level = %d\n", level); I915_WRITE(BLC_PWM_CTL, tmp | level); }