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.
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)
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 :(
Does disabling runpm help? Boot with radeon.runpm=0 on the kernel command line in grub.
(In reply to comment #3) > Does disabling runpm help? Boot with radeon.runpm=0 on the kernel command > line in grub. yes it does :)
thank you
Please attach your dmesg output. Is this a muxed or muxless laptop?
Created attachment 99349 [details] [review] possible fix Does the attached patch help?
Created attachment 99424 [details] dmesg output before patching (and with runpm)
(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.
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?
(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)
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".
Forgot to say : this is a muxed laptop.
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.
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
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.