Regression: drm/radeon: brightness control hard system lockup

[Alex Deucher]

On Sun, Jan 6, 2013 at 7:59 AM, Eldad Zack <eldad at fogrefinery.com> 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.

Alex