Hi,
On Fri, Nov 5, 2021 at 11:34 AM Lyude Paul lyude@redhat.com wrote:
As it turns out, apparently some machines will actually leave additional backlight functionality like dynamic backlight control on before the OS loads. Currently we don't take care to disable unsupported features when writing back the backlight mode, which can lead to some rather strange looking behavior when adjusting the backlight.
So, let's fix this by just not reading back the current backlight mode on initial enable. I don't think there should really be any downsides to this, and this will ensure we don't leave any unsupported functionality enabled.
This should fix at least one (but not all) of the issues seen with DPCD backlight support on fi-bdw-samus
v5:
- Just avoid reading back DPCD register - Doug Anderson
Signed-off-by: Lyude Paul lyude@redhat.com Fixes: 867cf9cd73c3 ("drm/dp: Extract i915's eDP backlight code into DRM helpers")
drivers/gpu/drm/drm_dp_helper.c | 40 ++++++++++----------------------- 1 file changed, 12 insertions(+), 28 deletions(-)
You forgot to CC me on this one! ;-)
This looks good to me now, so FWIW:
Reviewed-by: Douglas Anderson dianders@chromium.org