From: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx> [Why] If the "max bpc" isn't explicitly set in the atomic state then it have a value of 0. This has the correct behavior of limiting a panel to 8bpc in the case where the panel supports 8bpc. In the case of eDP panels this isn't a true assumption - there are panels that can only do 6bpc. Banding occurs for these displays. [How] Initialize the max_bpc when the connector resets to 8bpc. Also carry over the value when the state is duplicated. Bugzilla: https://bugs.freedesktop.org/108825 Fixes: 307638884f72 ("drm/amd/display: Support amdgpu "max bpc" connector property") Backport of commit 49f1c44b581b08e3289127ffe58bd208c3166701 upstream. Fixes regression caused by the automatic patch select of these two patches: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/gpu/drm/amd?h=linux-4.19.y&id=a0c25b4098b8de23f34f81860ddc3cbaaa159189 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/gpu/drm/amd?h=linux-4.19.y&id=3374518d4d1ae021dc60885f4ea8dca0a3ca290f Bug: https://bugs.freedesktop.org/show_bug.cgi?id=109122 Cc: Sasha Levin <sashal@xxxxxxxxxx> Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx> Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> (cherry picked from commit 49f1c44b581b08e3289127ffe58bd208c3166701) Cc: <stable@xxxxxxxxxxxxxxx> # 4.19.x --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 299def84e69c..d792735f1365 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -2894,6 +2894,7 @@ void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector) state->underscan_enable = false; state->underscan_hborder = 0; state->underscan_vborder = 0; + state->max_bpc = 8; __drm_atomic_helper_connector_reset(connector, &state->base); } @@ -2911,6 +2912,7 @@ amdgpu_dm_connector_atomic_duplicate_state(struct drm_connector *connector) if (new_state) { __drm_atomic_helper_connector_duplicate_state(connector, &new_state->base); + new_state->max_bpc = state->max_bpc; return &new_state->base; } -- 2.20.1
