On Mon, 14 Jan 2013, Alex Deucher wrote: > On Sun, Jan 13, 2013 at 4:00 PM, Eldad Zack <eldad@xxxxxxxxxxxxxxx> wrote: > > > > On Mon, 7 Jan 2013, Alex Deucher wrote: > >> On Mon, Jan 7, 2013 at 4:33 PM, Eldad Zack <eldad@xxxxxxxxxxxxxxx> wrote: > >> > > >> > On Mon, 7 Jan 2013, Alex Deucher wrote: > >> >> On Sun, Jan 6, 2013 at 7:59 AM, Eldad Zack <eldad@xxxxxxxxxxxxxxx> wrote: > >> >> > > >> >> > Hi Alex, > >> >> > > >> >> > Commit 0ecebb9e0d14e9948e0b1529883a776758117d6f "drm/radeon: switch to a > >> >> > finer grained reset for evergreen" introduced a hard system lockup to my > >> >> > setup. I found it after bisecting, and confirmed it by reverting it on > >> >> > the latest mainline ( 5f243b9 ). > >> >> > > >> >> > This: > >> >> > > >> >> > echo 7 > /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/backlight/acpi_video0/brightness > >> >> > > >> >> > Causes a hard lock-up hard, i.e. immediate freeze, without any logs. > >> >> > > >> >> > See lspci output and kernel .config below. > >> >> > If there's any more info I can provide, please let me know. > >> >> > >> >> Do you normally see GPU resets when changing the backlight? Please > >> >> attach your dmesg output when changing the backlight with the patch > >> >> reverted. > >> > > >> > I see nothing. Just to make sure, I cleared the buffer, cycled through > >> > 0-7 a couple of hunderd times (until the flicker annoyed), but I see no > >> > messages at all. > >> > Is there any debug config I should turn on? > >> > >> Can you try adding a printk() in evergreen_asic_reset() and see if it > >> is somehow getting called when you change the brightness? When you > >> use the apci backlight control, the radeon driver is not involved at > >> all. They only way the driver would get involved is if the acpi > >> backlight control somehow caused the GPU to hang and then the driver > >> detected the hang and attempted to reset the GPU. I don't see any > >> evidence of a GPU reset in your kernel log however. Note that the > >> driver also registers native backlight contol. Does that work any > >> better than acpi? > > > > The native backlight controls work very well. Thanks for that, I didn't > > even noticed that. It has finer control over brightness too. > > > > I worked out a fix for the problem, but I think it's not a proper one. > > What I noticed is that evergreen_gpu_soft_reset() is only ever called > > once on my system, at boot. > > Then I realized from the dmesg that neither > > evergreen_gpu_soft_reset_dma() nor evergreen_gpu_soft_reset_gfx() actually > > do anything. Both return on the first if statements there. > > > > So as far as I can tell, the difference your patch introduced is calling > > evergreen_mc_stop() and evergreen_mc_resume(), which somehow puts my > > system in some state that ACPI brightness control leads to a lock up. > > > > BTW, I don't see a GPU reset happening at all - I also tried suspend/resume > > and starting an OpenGL application. Do you know how I can trigger it? > > > > To fix this, I moved the GUI_ACTIVE test before evergreen_mc_stop(), but > > I think it just masks the issue. > > Patch below (against latest HEAD) just in case. > > > > Thanks for tracking this down. The attached patch should fix the > issue properly. Thanks, I just applied it and it works as expected. Tested-by: Eldad Zack <eldad@xxxxxxxxxxxxxxx> @Paul: Thanks for the comments, will do so in the future. Cheers, Eldad _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
