| Summary: | [GM45] failure to control backlight | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Product: | DRI | Reporter: | christobzr | ||||||
| Component: | DRM/Intel | Assignee: | Daniel Vetter <daniel> | ||||||
| Status: | CLOSED INVALID | QA Contact: | Intel GFX Bugs mailing list <intel-gfx-bugs> | ||||||
| Severity: | major | ||||||||
| Priority: | medium | CC: | alan.zimm, ben, chris, christobzr, eugeni, gentoo-bugs, jani.nikula, jbarnes | ||||||
| Version: | XOrg git | ||||||||
| Hardware: | x86-64 (AMD64) | ||||||||
| OS: | Linux (All) | ||||||||
| Whiteboard: | |||||||||
| i915 platform: | i915 features: | ||||||||
| Attachments: |
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Description
christobzr
2011-08-29 04:58:45 UTC
Created attachment 50656 [details]
xorg log
Created attachment 50657 [details]
dmesg output (with boot option "drm.debug=0x06")
The question to be asked is "which driver is the system missing that controls the backlight?" > The question to be asked is "which driver is the system missing that controls > the backlight?" I'm not sure how to answer that question. In gentoo I compiled my own kernel with the following modules built in : -> Device Drivers -> Graphics support -> Backlight & LCD device support -> Lowlevel LCD controls -> Platform LCD controls -> Generic (aka Sharp Corgi) Backlight Driver Here is my full kernel configuration : http://pastebin.com/ViRaaESF As suggested here http://forums.gentoo.org/viewtopic-p-6797468.html#6797468 , adding "acpi_osi= " or "acpi_osi=Linux" to the kernel boot command line in grub, lets me adjust brightness with the keys provided on the laptop (Fn + left/right arrow). I added "acpi_osi=Linux" to grub so the machine now always boots with this parameter. It still boots to a blank screen, but I can press Fn + left arrow to switch the backlight on. Afterwards I can adjust the brightness with the keyboard controls. The gnome-power-manager based brightness control applet does not work however. Can I provide any further information ? If I'm not correctly describing the problem, is there somewhere I can go for advice ? Am I to understand that this is not a problem in the Intel driver ? I think it is one of the backlight issues, similar to #41306 or #36823. There was one recent patch about a similar issue - http://lkml.org/lkml/2011/10/13/95 - could you try with it please? Thanks for the feedback ! I patched my kernel with the suggested patch - same issue. I would guess from the description of the patch that this is not the issue here : the patch seems to concern the backlight being set to wrong brightness when it goes up (not any incapacity to adjust brightness). This bug however is different, I will resume the issue a little more concisely. If you just boot the system, the backlight is off and cannot be turned on with the brightness keys. If you can login without seeing what is on the screen, you can turn the backlight on with the command "setpci -s 00:02.0 F4.B=00", but it cannot be adjusted by keys or software, and will turn back off after lid shut, screensaver etc. Adding "acpi_osi=Linux" to the kernel boot command line lets you switch on and adjust the backlight with the brightness keys after boot, but it cannot be adjusted by software. On boot the backlight is always off. Annoying consequences : system cannot dim display when idle or when on battery. More banter here : http://dodonov.net/blog/2011/10/14/so-whats-been-up-with-intel-linux-graphics-this-week/ This bug seems to concern many people : google gives tens of threads/bugs for issues with the same symptoms. ie : https://bugs.launchpad.net/ubuntu/+source/linux/+bug/752165 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/740893 http://markuswalther.com/tech/backlight.html If it is a regression from previous kernel, I guess that the easiest way to get it solved by bisecting it to the patch which caused the problem.. @christobzr, as you can reproduce the problem consistently, could you do it for us please? Thanks! *** Bug 44156 has been marked as a duplicate of this bug. *** Btw, yes I will be happy to do the tests, however I do not currently have the machine... Daniel is working on some patches to fix the backlight controller and is looking for victims^Wtesters. Ok, I've created these patches, available at http://cgit.freedesktop.org/~danvet/drm/log/?h=backlight-confusion Git link is git://people.freedesktop.org/~danvet/drm backlight-confusion Please test them, thanks. (In reply to comment #15) > Ok, I've created these patches, available at > http://cgit.freedesktop.org/~danvet/drm/log/?h=backlight-confusion > > Git link is git://people.freedesktop.org/~danvet/drm backlight-confusion > > Please test them, thanks. Updated patches and discussion at [1], also available in the "backlight" branch of [2]. Please test. [1] http://thread.gmane.org/gmane.comp.freedesktop.xorg.drivers.intel/13642 [2] git://gitorious.org/jani/drm.git Please try i915.invert_brightness=1 module parameter with kernel version v3.5 or later, see if that fixes the brightness issue, and report 'lspci -vmmnn' if it does. If someone finds the time to test and this is still an issue, please re-open |
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