Commit 8e3a1c50 authored Nov 28, 2018 by Nicholas Kazlauskas Committed by Greg Kroah-Hartman Jan 13, 2019

drm/amd/display: Fix unintialized max_bpc state values

commit 49f1c44b581b08e3289127ffe58bd208c3166701 upstream.

[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")

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 5f0ab980

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -2894,6 +2894,7 @@ void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector)
	state->underscan_enable = false;		state->underscan_enable = false;
	state->underscan_hborder = 0;		state->underscan_hborder = 0;
	state->underscan_vborder = 0;		state->underscan_vborder = 0;
			state->max_bpc = 8;

	__drm_atomic_helper_connector_reset(connector, &state->base);		__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) {		if (new_state) {
	__drm_atomic_helper_connector_duplicate_state(connector,		__drm_atomic_helper_connector_duplicate_state(connector,
	&new_state->base);		&new_state->base);
			new_state->max_bpc = state->max_bpc;
	return &new_state->base;		return &new_state->base;
	}		}