diff options
| author | Anthony Koo <Anthony.Koo@amd.com> | 2018-10-12 21:34:32 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2018-11-05 14:21:39 -0500 |
| commit | 262485a50fd4532a8d71165190adc7a0a19bcc9e (patch) | |
| tree | 60819d7cabbd30625d27bbd05841e239fdca29c3 /drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | |
| parent | a7d8084b589714ea08bddd3720986b657840f46b (diff) | |
drm/amd/display: Expand dc to use 16.16 bit backlight
[Why] We want to increase precision for backlight setting.
But DC interface takes 8 bit backlight level value only.
[How] DMCU already takes 16 bit backlight level.
Expand the DC interface to take 16.16 bit value.
Max 32 bit backlight value (0xFFFF) will represent
max backlight (100%)
Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c')
| -rw-r--r-- | drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 8 |
1 files changed, 7 insertions, 1 deletions
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 a3849e161593..67b547c64a3e 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -1580,8 +1580,14 @@ static int amdgpu_dm_backlight_update_status(struct backlight_device *bd) */ if (bd->props.brightness < 1) return 1; + + /* backlight_pwm_u16_16 parameter is in unsigned 32 bit, 16 bit integer + * and 16 bit fractional, where 1.0 is max backlight value. + * bd->props.brightness is 8 bit format and needs to be converted by + * scaling via copy lower byte to upper byte of 16 bit value. + */ if (dc_link_set_backlight_level(dm->backlight_link, - bd->props.brightness, 0, 0)) + (bd->props.brightness * 0x101), 0, 0)) return 0; else return 1; |