Commit 694d0775 authored by David Francis's avatar David Francis Committed by Alex Deucher

drm/amd: Don't fail on backlight = 0

Amgpu's backlight update status function was
returning 1 (an error value) when the backlight
property was 0.  This breaks users that assume
0 is a valid backlight value (which is a
correct assumption)

If the user passes in a backlight value of 0,
tell them everything is fine, then write a value of
1 to hardware.
Signed-off-by: default avatarDavid Francis <David.Francis@amd.com>
Bugzilla: https://bugs.freedesktop.org/108668
Fixes: 416615ea9578 ("drm/amd/display: set backlight level limit to 1")
Cc: Suresh.Guttula@amd.com
Cc: Harry.Wentland@amd.com
Cc: Samantham@posteo.net
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 45cf8c23
...@@ -1573,21 +1573,23 @@ static int amdgpu_dm_backlight_update_status(struct backlight_device *bd) ...@@ -1573,21 +1573,23 @@ static int amdgpu_dm_backlight_update_status(struct backlight_device *bd)
{ {
struct amdgpu_display_manager *dm = bl_get_data(bd); struct amdgpu_display_manager *dm = bl_get_data(bd);
/* 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.
*/
uint32_t brightness = bd->props.brightness * 0x101;
/* /*
* PWM interperts 0 as 100% rather than 0% because of HW * PWM interperts 0 as 100% rather than 0% because of HW
* limitation for level 0.So limiting minimum brightness level * limitation for level 0. So limiting minimum brightness level
* to 1. * to 1.
*/ */
if (bd->props.brightness < 1) if (bd->props.brightness < 1)
return 1; brightness = 0x101;
/* 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, if (dc_link_set_backlight_level(dm->backlight_link,
(bd->props.brightness * 0x101), 0, 0)) brightness, 0, 0))
return 0; return 0;
else else
return 1; return 1;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment