On Fri, 05 Feb 2021 17:36:44 +0100, Alex Deucher wrote:
On Wed, Feb 3, 2021 at 7:42 AM Takashi Iwai tiwai@suse.de wrote:
The current code tries to read the brightness value via dc_link_get_backlight_level() no matter whether it's controlled via aux or not, and this results in a bogus value returned. Fix it to read the current value via dc_link_get_backlight_level_nits() for the aux.
BugLink: https://bugzilla.opensuse.org/show_bug.cgi?id=1180749 BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1438 Signed-off-by: Takashi Iwai tiwai@suse.de
This looks fine to me. FWIW, I have a similar patch set here: https://cgit.freedesktop.org/~agd5f/linux/log/?h=backlight_wip
I'm fine to scratch mine as long as the issue gets fixed :)
FWIW, the biggest problem so far was the aux channel backlight didn't work as expected, the actual backlight isn't changed by the backlight sysfs write. (And the sysfs read gives a bogus value, but it's not the cause of the non-working backlight control.)
Does the aux channel backlight really work with the current code? Or is this rather a device-specific issue (e.g. broken BIOS) and we might need to come up with a deny list or such?
thanks,
Takashi