|Summary:||backlight switches off when starting X - since kernel-3.13|
|Component:||DRM/Radeon||Assignee:||Default DRI bug account <dri-devel>|
|Status:||RESOLVED FIXED||QA Contact:|
|i915 platform:||i915 features:|
Description nl 2014-03-08 19:17:40 UTC
After updating from linux 3.12.8 to 3.13 my display backlight switches off when starting X. The kernel doesn't crash, it just switched off the backlight. Hardware name: Acer Aspire 3820T/JM31_CP, BIOS V1.19 10/27/2010 This is a notebook with an intel/radeon hybrid graphics. I use intel for my X. I report this as radeon problem because git bisect (on linux-stable tree) showed the following commit as the cause of my problem: 10ebc0bc09344ab6310309169efc73dfe6c23d72 is the first bad commit commit 10ebc0bc09344ab6310309169efc73dfe6c23d72 Author: Dave Airlie <airlied at redhat.com> Date: Mon Sep 17 14:40:31 2012 +1000 drm/radeon: add runtime PM support (v2) This hooks radeon up to the runtime PM system to enable dynamic power management for secondary GPUs in switchable and powerxpress laptops. v2: agd5f: clean up, add module parameter Signed-off-by: Dave Airlie <airlied at redhat.com> Signed-off-by: Alex Deucher <alexander.deucher at amd.com> Please let me know if you need addititonal information.
Comment 1 Yuanjie 2014-03-14 05:39:57 UTC
I have the same problem with radeon/intel laptop: 00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 18) 02:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Madison [Mobility Radeon HD 5650/5750 / 6530M/6550M] (rev ff)
Comment 2 nl 2014-05-17 21:35:17 UTC
As the problem still exists and prevents me from using any kernel 3.13+ I changed the priority of this bug. When I did the git bisect I hoped it would help to find a solution soon. Is there anything I can do to help fixing this problem? I don't want to get stuck on kernel 3.12.20 :(
Comment 3 Alex Deucher 2014-05-19 02:08:22 UTC
Does disabling runpm help? Boot with radeon.runpm=0 on the kernel command line in grub.
Comment 4 nl 2014-05-19 17:37:10 UTC
(In reply to comment #3) > Does disabling runpm help? Boot with radeon.runpm=0 on the kernel command > line in grub. yes it does :)
Comment 5 nl 2014-05-19 17:37:37 UTC
Comment 6 Alex Deucher 2014-05-19 17:44:53 UTC
Please attach your dmesg output. Is this a muxed or muxless laptop?
Comment 7 Alex Deucher 2014-05-19 18:11:23 UTC
Created attachment 99349 [details] [review] possible fix Does the attached patch help?
Comment 8 nl 2014-05-20 15:32:36 UTC
Created attachment 99424 [details] dmesg output before patching (and with runpm)
Comment 9 nl 2014-05-20 15:35:47 UTC
(In reply to comment #7) > Does the attached patch help? The patch works fine, however the display backlight switches off for several seconds during X init now (it didn't with kernel 2.12) but this is not really a problem, as it comes back happily :) thank you.
Comment 10 Alex Deucher 2014-05-20 15:44:20 UTC
Created attachment 99427 [details] [review] possible fix v2 (In reply to comment #9) > The patch works fine, however the display backlight switches off for several > seconds during X init now (it didn't with kernel 2.12) but this is not > really a problem, as it comes back happily :) thank you. Does this patch work any better?
Comment 11 nl 2014-05-20 20:43:59 UTC
(In reply to comment #10) > Created attachment 99427 [details] [review] [review] > possible fix v2 > Does this patch work any better? No, pretty much the same behaviour as the first version here. The backlight switches off when X starts, and comes backs ~5 seconds later. (same delay in restoring backlight after resume from suspend)
Comment 12 sfievet 2014-06-14 12:47:21 UTC
I am affected by this bug too. I have a Acer 3820TG laptop featuring Intel IGP (Ironlake) / AMD DGP (Radeon 6550M). It kept me stucked with kernel 3.12 series until I googled for "backlight issue" rather than "Intel driver issue" and found THIS bug report. :-) adding radeon.runpm=0 to the boot options works for me too. I haven't tested the patch yet. FWIW, I'd like to add 2 side informations hoping it might be related : - the backlight control only works for the Intel IGP. If the laptop goes idle when on the radeon, waking it up doesn't bring the backlight back. - when switching from Ironlake to Radeon through VGA switcheroo, I have to use "ON -> MIGD -> DDIS" sequence as the screen goes black immediately after passing "ON".
Comment 13 sfievet 2014-06-14 14:15:06 UTC
Forgot to say : this is a muxed laptop.
Comment 14 Alex Deucher 2014-06-16 15:23:06 UTC
Fix is upstream: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f2bc561610962693be61425cf913778586d8f9c1 and will make it's way back to stable kernels as well.
Comment 15 sfievet 2014-06-16 19:28:45 UTC
I just applied the fixed against 3.15.0, and it does work as reported. The 5s delay at X startup is a bit annoying but acceptable... In my case it actually happens twice : - at X startup - at session start (presumably when the XFCE power manager tool starts up) Thank you for helping us out