[PATCH] drm/amd/display: Allow backlight to go below `AMDGPU_DM_DEFAULT_MIN_BACKLIGHT`

Harry Wentland harry.wentland at amd.com
Mon Sep 16 20:09:48 UTC 2024


On 2024-09-15 15:28, Mario Limonciello wrote:
> From: Mario Limonciello <mario.limonciello at amd.com>
> 
> The issue with panel power savings compatibility below
> `AMDGPU_DM_DEFAULT_MIN_BACKLIGHT` happens at
> `AMDGPU_DM_DEFAULT_MIN_BACKLIGHT` as well.
> 
> That issue will be fixed separately, so don't prevent the backlight
> brightness from going that low.
> 
> Cc: Harry Wentland <harry.wentland at amd.com>
> Cc: Thomas Weißschuh <linux at weissschuh.net>
> Link: https://lore.kernel.org/amd-gfx/be04226a-a9e3-4a45-a83b-6d263c6557d8@t-8ch.de/T/#m400dee4e2fc61fe9470334d20a7c8c89c9aef44f
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>

Reviewed-by: Harry Wentland <harry.wentland at amd.com>

Harry

> ---
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> 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 ad66f09cd0bb..80b8594fcc33 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -4449,7 +4449,7 @@ static void amdgpu_dm_update_backlight_caps(struct amdgpu_display_manager *dm,
>  		int spread = caps.max_input_signal - caps.min_input_signal;
>  
>  		if (caps.max_input_signal > AMDGPU_DM_DEFAULT_MAX_BACKLIGHT ||
> -		    caps.min_input_signal < AMDGPU_DM_DEFAULT_MIN_BACKLIGHT ||
> +		    caps.min_input_signal < 0 ||
>  		    spread > AMDGPU_DM_DEFAULT_MAX_BACKLIGHT ||
>  		    spread < AMDGPU_DM_MIN_SPREAD) {
>  			DRM_DEBUG_KMS("DM: Invalid backlight caps: min=%d, max=%d\n",



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