diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.19.8/0660-drm-amd-display-set-backlight-level-limit-to-1.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.19.8/0660-drm-amd-display-set-backlight-level-limit-to-1.patch | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.19.8/0660-drm-amd-display-set-backlight-level-limit-to-1.patch b/common/recipes-kernel/linux/linux-yocto-4.19.8/0660-drm-amd-display-set-backlight-level-limit-to-1.patch new file mode 100644 index 00000000..dd1eb9a2 --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.19.8/0660-drm-amd-display-set-backlight-level-limit-to-1.patch @@ -0,0 +1,44 @@ +From 62c9ca9cd1bc0e0f78b9890945b518504403c0d0 Mon Sep 17 00:00:00 2001 +From: "Guttula, Suresh" <Suresh.Guttula@amd.com> +Date: Mon, 29 Oct 2018 05:23:25 +0000 +Subject: [PATCH 0660/2940] drm/amd/display: set backlight level limit to 1 + +This patch will work as workaround for silicon limitation +related to PWM dutycycle when the backlight level goes to 0. + +Actually PWM value is 16 bit value and valid range from 1-65535. +when ever user requested to set this PWM value to 0 which is not +fall in the range, in VBIOS taken care this by limiting to 1. +This patch here will do the same. Either driver or VBIOS can not +pass 0 value as it is not a valid range for PWM and it will +give a high PWM pulse which is not the intended behaviour as +per HW constraints. + +Signed-off-by: suresh guttula <suresh.guttula@amd.com> +Reviewed-by: Harry Wentland <harry.wentland@amd.com> +Signed-off-by: Alex Deucher <alexander.deucher@amd.com> +--- + drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 7 +++++++ + 1 file changed, 7 insertions(+) + +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 d90f15605161..16115ca7a0d6 100644 +--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c ++++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +@@ -1523,6 +1523,13 @@ static int amdgpu_dm_backlight_update_status(struct backlight_device *bd) + { + struct amdgpu_display_manager *dm = bl_get_data(bd); + ++ /* ++ * PWM interperts 0 as 100% rather than 0% because of HW ++ * limitation for level 0.So limiting minimum brightness level ++ * to 1. ++ */ ++ if (bd->props.brightness < 1) ++ return 1; + if (dc_link_set_backlight_level(dm->backlight_link, + bd->props.brightness, 0, 0)) + return 0; +-- +2.17.1 + |