| Summary: | [915GM] Screen flickers on backlight change | ||||||||||||||||
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| Product: | xorg | Reporter: | Sven Arvidsson <sa> | ||||||||||||||
| Component: | Driver/intel | Assignee: | Jesse Barnes <jbarnes> | ||||||||||||||
| Status: | RESOLVED FIXED | QA Contact: | Xorg Project Team <xorg-team> | ||||||||||||||
| Severity: | normal | ||||||||||||||||
| Priority: | medium | CC: | ynvich | ||||||||||||||
| Version: | 7.4 (2008.09) | ||||||||||||||||
| Hardware: | x86 (IA32) | ||||||||||||||||
| OS: | Linux (All) | ||||||||||||||||
| Whiteboard: | |||||||||||||||||
| i915 platform: | i915 features: | ||||||||||||||||
| Attachments: |
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Created attachment 24796 [details]
xorg log using modedebug
Created attachment 24797 [details]
dmesg log after brightness change
Created attachment 24798 [details]
xrandr verbose output
Can you try the patch at https://bugs.freedesktop.org/attachment.cgi?id=24651? This looks like pipe underruns based on the video, but I'd like to be sure. Backlight control seems a lot more well behaved after applying the patch, no flicker. Unfortunately I now get flickering almost constantly when there is large changes to the screen (moving windows around etc.) and the log file is filled with errors about "underrun on pipe B!". Oh interesting... Can you attach your log containing a few of the underruns? Created attachment 24831 [details]
xorg log using i830-fifo-wm-only-8.patch
Sure. This is the log just after logging in and launching gnome-terminal.
Created attachment 27065 [details] [review] FIFO setup patch for KMS Is it possible for you to use KMS on this machine? If so, can you give this patch a try? With KMS and the patch applied, things seems to work fine. There's no more flicker when xrandr is run or when gnome-power-manager adjusts the backlight. But for some reason, xbacklight reports "No outputs have backlight property" and they are indeed gone from the verbose output of xrandr. Maybe this is normal? Ok good to hear. Yeah, with KMS the backlight is controlled through /sys/class/backlight. We may not expose it via a property at all... By the way, will this patch make it for 2.6.31? Yeah, that's the goal. I'll close this with a link to the commit when that happens. Fix pushed, thanks for testing! author Shaohua Li <shaohua.li@intel.com> commit 7662c8bd6545c12ac7b2b39e4554c3ba34789c50 drm/i915: add FIFO watermark support |
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Created attachment 24795 [details] eee screen flicker My Asus Eee PC 701 4G suffers from horrible screen flickering any time the brightness of the backlight is adjusted. I'm attaching a video to the bug report, which shows the backlight being adjusted from 100 to 90% using xbacklight. This happens both with git master, and at least as far back as 2.6.1. I have only just now been bothered by this bug as gnome-power-manager now seems to use randr to adjust the brightness. I also get a short, hardly noticeable flicker any time xrandr is invoked, but I guess it's probing the backlight. I have tried: - Turning FramebufferCompression off - Switching between EXA and UXA - Testing the between the backlight controls (native, legacy, combination and kernel) - Going back to using kernel 2.6.26 but none of these have any effect. Changing the backlight using the hardware buttons on the keyboard, or echo'ing values to /sys/class/backlight/eeepc/brightness does however work with no problem. System environment: -- chipset: 910GML -- system architecture: 32-bit -- Linux distribution: Debian unstable -- Machine or mobo model: Asus Eee PC 701 4G (using latest BIOS from Asus) -- Display connector: LVDS -- xf86-video-intel: 9b615a52671aacf34666f90ecfff98651ce6afe2 -- mesa: 7.4 -- xserver: 1.6.0 -- drm: 07646002c6835537c6ae44ef9b3f8480762279b8 -- kernel: 2.6.29