diff options
| author | Iswara Nagulendran <[email protected]> | 2023-09-29 11:20:46 -0400 |
|---|---|---|
| committer | Alex Deucher <[email protected]> | 2023-10-26 19:02:22 -0400 |
| commit | b231933da7d6be53d08139f8adf2560a90b47ca9 (patch) | |
| tree | c9bd2b20430ea88274f870ae26a4cb9bef47fa47 | |
| parent | 1b9ec7cb424441de67d09c3abad46467f82ff161 (diff) | |
drm/amd/display: Read before writing Backlight Mode Set Register
[HOW&WHY]
Reading the value from
DP_EDP_BACKLIGHT_MODE_SET_REGISTER, DPCD 0x721
before setting the
BP_EDP_PANEL_LUMINANC_CONTROL_ENABLE bit
to ensure there are no accidental overwrites.
Reviewed-by: Sreeja Golui <[email protected]>
Reviewed-by: Harry Vanzylldejong <[email protected]>
Acked-by: Roman Li <[email protected]>
Signed-off-by: Iswara Nagulendran <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c index 86f97ddcc595..e32a7974a4bc 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c @@ -182,7 +182,7 @@ bool edp_set_backlight_level_nits(struct dc_link *link, &backlight_control, 1) != DC_OK) return false; } else { - const uint8_t backlight_enable = DP_EDP_PANEL_LUMINANCE_CONTROL_ENABLE; + uint8_t backlight_enable = 0; struct target_luminance_value *target_luminance = NULL; //if target luminance value is greater than 24 bits, clip the value to 24 bits @@ -191,6 +191,11 @@ bool edp_set_backlight_level_nits(struct dc_link *link, target_luminance = (struct target_luminance_value *)&backlight_millinits; + core_link_read_dpcd(link, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, + &backlight_enable, sizeof(uint8_t)); + + backlight_enable |= DP_EDP_PANEL_LUMINANCE_CONTROL_ENABLE; + if (core_link_write_dpcd(link, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &backlight_enable, sizeof(backlight_enable)) != DC_OK) |