On Mon, 2019-10-21 at 15:44 -0400, sunpeng.li@xxxxxxx wrote: > From: Leo Li <sunpeng.li@xxxxxxx> > > [Why] > > Some LED panel drivers might not like fractional PWM. In such cases, > backlight flickering may be observed. > > [How] > > Add a DC feature mask to disable fractional PWM, and associate it with > the preexisting dc_config flag. > > The flag is only plumbed through the dmcu firmware, so plumb it through > the driver path as well. > > To disable, add the following to the linux cmdline: > amdgpu.dcfeaturemask=0x4 > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204957 > Signed-off-by: Leo Li <sunpeng.li@xxxxxxx> > --- > > v2: Add bugzilla link > > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +++ > drivers/gpu/drm/amd/display/dc/dce/dce_abm.c | 4 ++++ > drivers/gpu/drm/amd/include/amd_shared.h | 1 + > 3 files changed, 8 insertions(+) Tested on Ubuntu 19.04, vanilla v5.3.7 kernel with the patch applied and amdgpu.dcfeaturemask=0x4 added to the kernel command line, no issues after 8 reboots. (The issue could be reproduced without amdgpu.dcfeaturemask=0x4 on first boot.) Tested-by: Lukáš Krejčí <lskrejci@xxxxxxxxx> _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
