On Wed, Jul 31, 2024 at 08:40:12PM +0300, Jani Nikula wrote: > On Wed, 31 Jul 2024, Thomas Weißschuh <linux@xxxxxxxxxxxxxx> wrote: > > The value of "min_input_signal" returned from ATIF on a Framework AMD 13 > > is "12". This leads to a fairly bright minimum display backlight. > > > > Add a generic override helper for the user to override the settings > > provided by the firmware through the kernel cmdline. > > Also add amdgpu as a user of that helper. > > > > One solution would be a fixed firmware version, which was announced but > > has no timeline. > > The flip side is that if we add this now, it pretty much has a timeline: > We'll have to carry and support it forever. > > It's not a great prospect for something so specific. Not to mention that > the limits are generally there for electrical minimums that should not > be overridden. And before you know it, we'll have bug reports about > flickering screens... Yeah I think for this specific case where a fixed firmware is already kinda promised, a quirk is the right fix. Otherwise we open up a can of worms here ... so personally I like v2 a lot more. -Sima > > BR, > Jani. > > > > > > This helper does conflict with the mode override via the cmdline. > > Only one can be specified. > > IMO the mode override can be extended to also handle "min-brightness" > > when that becomes necessary. > > > > --- > > Changes in v3: > > - Switch to cmdline override parameter > > - Link to v2: https://lore.kernel.org/r/20240623-amdgpu-min-backlight-quirk-v2-0-cecf7f49da9b@xxxxxxxxxxxxxx > > > > Changes in v2: > > - Introduce proper drm backlight quirk infrastructure > > - Quirk by EDID and DMI instead of only DMI > > - Limit quirk to only single Framework 13 matte panel > > - Link to v1: https://lore.kernel.org/r/20240610-amdgpu-min-backlight-quirk-v1-1-8459895a5b2a@xxxxxxxxxxxxxx > > > > --- > > Thomas Weißschuh (2): > > drm/connector: add drm_connector_get_cmdline_min_brightness_override() > > drm/amd/display: implement minimum brightness override > > > > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 6 ++++ > > drivers/gpu/drm/drm_connector.c | 34 +++++++++++++++++++++++ > > include/drm/drm_connector.h | 2 ++ > > 3 files changed, 42 insertions(+) > > --- > > base-commit: 36821612eb3091a21f7f4a907b497064725080c3 > > change-id: 20240610-amdgpu-min-backlight-quirk-8402fd8e736a > > > > Best regards, > > -- > Jani Nikula, Intel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
