Summary: | [snb] initial backlight brightness is zero | ||||||||
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Product: | DRI | Reporter: | Kirill Tkhai <tkhai> | ||||||
Component: | DRM/Intel | Assignee: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||||
Status: | CLOSED NOTOURBUG | QA Contact: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||||
Severity: | normal | ||||||||
Priority: | medium | CC: | aaron.lu, intel-gfx-bugs, tkhai | ||||||
Version: | unspecified | ||||||||
Hardware: | Other | ||||||||
OS: | All | ||||||||
Whiteboard: | |||||||||
i915 platform: | i915 features: | ||||||||
Attachments: |
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Description
Kirill Tkhai
2013-10-07 21:58:22 UTC
Boot without backlight related kernel parameters, set drm.debug=0xe module parameter, and attach dmesg all the way from early boot to the problem. Do backlight hotkeys work? How is their polarity? Please mount debugfs and attach /sys/kernel/debug/dri/0/i915_opregion. Created attachment 87492 [details]
dmesg
Created attachment 87493 [details]
opregion
Hotkeys work, polarity is standard. Kernel loads complitely in dark. Starting of X server does not change brightness. Hotkeys do. Can you please check whether changing the brighetness through xrandr (with xrandr --output <output> --set Backlight <value>) and the raw interfaces in /sys/class/backlight/* also works? (In reply to comment #4) > Hotkeys work, polarity is standard. Kernel loads complitely in dark. > Starting of X server does not change brightness. Hotkeys do. So if you use invert_brightness, the polarity is reversed, right? (In reply to comment #5) > Can you please check whether changing the brighetness through xrandr (with > xrandr --output <output> --set Backlight <value>) and the raw interfaces in > /sys/class/backlight/* also works? Daniel, I'll check this a little later, when I'm near the laptop. (In reply to comment #6) > (In reply to comment #4) > > Hotkeys work, polarity is standard. Kernel loads complitely in dark. > > Starting of X server does not change brightness. Hotkeys do. > > So if you use invert_brightness, the polarity is reversed, right? Everything is right. Tric from bug 70386 doesn't work for me: brightness is not remembered between reboots, I have to increase it by hotkeys every boot. (In reply to comment #8) > (In reply to comment #5) > > So if you use invert_brightness, the polarity is reversed, right? > > Everything is right. Tric from bug 70386 doesn't work for me: brightness is > not remembered between reboots, I have to increase it by hotkeys every boot. What? So regardless of i915.invert_brightness setting, your brightness hotkeys work with the same, correct polarity? Also, what does 'ls /sys/class/backlight' output? (In reply to comment #9) > (In reply to comment #8) > > (In reply to comment #5) > > > So if you use invert_brightness, the polarity is reversed, right? > > > > Everything is right. Tric from bug 70386 doesn't work for me: brightness is > > not remembered between reboots, I have to increase it by hotkeys every boot. > > What? So regardless of i915.invert_brightness setting, your brightness > hotkeys work with the same, correct polarity? In case of i915.invert_brightness set, the polarity is reversed. Ok, it looks like I understood invert_brightness wrong. The real problem is that initial brightness is zero. If I boot without parameters: $ cat /sys/class/backlight/acpi_video0/brightness 0 $ cat /sys/class/backlight/intel_backlight/brightness 0 What if you try the acpi_osi="!Windows 2012" kernel parameter? (In reply to comment #12) > What if you try the acpi_osi="!Windows 2012" kernel parameter? Hmm, this was sandy bridge though... have you upgraded your bios? (I am not implying you should, I'm merely asking.) Another module parameter to try: video.use_bios_initial_backlight=0. (In reply to comment #13) > (In reply to comment #12) > > What if you try the acpi_osi="!Windows 2012" kernel parameter? > > Hmm, this was sandy bridge though... have you upgraded your bios? (I am not > implying you should, I'm merely asking.) No yet. I'll try to do upgrade too. (In reply to comment #14) > Another module parameter to try: video.use_bios_initial_backlight=0. Thanks a lot! This solves the problem. Initial values are maximum: $ cat /sys/class/backlight/acpi_video0/brightness 100 $ cat /sys/class/backlight/intel_backlight/brightness 4845 (In reply to comment #15) > (In reply to comment #13) > > Hmm, this was sandy bridge though... have you upgraded your bios? (I am not > > implying you should, I'm merely asking.) > > No yet. I'll try to do upgrade too. Please don't. That may lead to more problems. > (In reply to comment #14) > > Another module parameter to try: video.use_bios_initial_backlight=0. > > Thanks a lot! This solves the problem. Initial values are maximum: > > $ cat /sys/class/backlight/acpi_video0/brightness > 100 > > $ cat /sys/class/backlight/intel_backlight/brightness > 4845 Cool! Closing as NOTOURBUG. Please file a new bug on Power-Video component at the kernel.org bugzilla [1]. Reference this bug and that video.use_bios_initial_backlight=0 fixes the issue, and attach output of 'dmidecode' there. [1] https://bugzilla.kernel.org/enter_bug.cgi?product=ACPI (In reply to comment #16) > Please file a new bug on Power-Video component at the kernel.org bugzilla > [1]. Reference this bug and that video.use_bios_initial_backlight=0 fixes > the issue, and attach output of 'dmidecode' there. Ok. Thanks again. |
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