diff options
Diffstat (limited to 'sys-kernel_arch-sources-g14_files_0005-drm-amd-display-use-correct-scale-for-actual_brightness.patch')
-rw-r--r-- | sys-kernel_arch-sources-g14_files_0005-drm-amd-display-use-correct-scale-for-actual_brightness.patch | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/sys-kernel_arch-sources-g14_files_0005-drm-amd-display-use-correct-scale-for-actual_brightness.patch b/sys-kernel_arch-sources-g14_files_0005-drm-amd-display-use-correct-scale-for-actual_brightness.patch new file mode 100644 index 000000000000..3a42f21e2d14 --- /dev/null +++ b/sys-kernel_arch-sources-g14_files_0005-drm-amd-display-use-correct-scale-for-actual_brightness.patch @@ -0,0 +1,143 @@ +Documentation for sysfs backlight level interface requires that +values in both 'brightness' and 'actual_brightness' files are +interpreted to be in range from 0 to the value given in the +'max_brightness' file. + +With amdgpu, max_brightness gives 255, and values written by the user +into 'brightness' are internally rescaled to a wider range. However, +reading from 'actual_brightness' gives the raw register value without +inverse rescaling. This causes issues for various userspace tools such +as PowerTop and systemd that expect the value to be in the correct +range. + +Introduce a helper to retrieve internal backlight range. Use it to +reimplement 'convert_brightness' as 'convert_brightness_from_user' and +introduce 'convert_brightness_to_user'. + +Bug: https://bugzilla.kernel.org/show_bug.cgi?id=203905 +Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1242 +Cc: Alex Deucher <alexander.deucher@amd.com> +Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com> +Signed-off-by: Alexander Monakov <amonakov@ispras.ru> +--- +v2: split convert_brightness to &_from_user and &_to_user (Nicholas) + + .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 81 +++++++++---------- + 1 file changed, 40 insertions(+), 41 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 710edc70e37e..b60a763f3f95 100644 +--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c ++++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +@@ -2881,51 +2881,50 @@ static int set_backlight_via_aux(struct dc_link *link, uint32_t brightness) + return rc ? 0 : 1; + } + +-static u32 convert_brightness(const struct amdgpu_dm_backlight_caps *caps, +- const uint32_t user_brightness) ++static int get_brightness_range(const struct amdgpu_dm_backlight_caps *caps, ++ unsigned *min, unsigned *max) + { +- u32 min, max, conversion_pace; +- u32 brightness = user_brightness; +- + if (!caps) +- goto out; ++ return 0; + +- if (!caps->aux_support) { +- max = caps->max_input_signal; +- min = caps->min_input_signal; +- /* +- * The brightness input is in the range 0-255 +- * It needs to be rescaled to be between the +- * requested min and max input signal +- * It also needs to be scaled up by 0x101 to +- * match the DC interface which has a range of +- * 0 to 0xffff +- */ +- conversion_pace = 0x101; +- brightness = +- user_brightness +- * conversion_pace +- * (max - min) +- / AMDGPU_MAX_BL_LEVEL +- + min * conversion_pace; ++ if (caps->aux_support) { ++ // Firmware limits are in nits, DC API wants millinits. ++ *max = 1000 * caps->aux_max_input_signal; ++ *min = 1000 * caps->aux_min_input_signal; + } else { +- /* TODO +- * We are doing a linear interpolation here, which is OK but +- * does not provide the optimal result. We probably want +- * something close to the Perceptual Quantizer (PQ) curve. +- */ +- max = caps->aux_max_input_signal; +- min = caps->aux_min_input_signal; +- +- brightness = (AMDGPU_MAX_BL_LEVEL - user_brightness) * min +- + user_brightness * max; +- // Multiple the value by 1000 since we use millinits +- brightness *= 1000; +- brightness = DIV_ROUND_CLOSEST(brightness, AMDGPU_MAX_BL_LEVEL); ++ // Firmware limits are 8-bit, PWM control is 16-bit. ++ *max = 0x101 * caps->max_input_signal; ++ *min = 0x101 * caps->min_input_signal; + } ++ return 1; ++} + +-out: +- return brightness; ++static u32 convert_brightness_from_user(const struct amdgpu_dm_backlight_caps *caps, ++ uint32_t brightness) ++{ ++ unsigned min, max; ++ ++ if (!get_brightness_range(caps, &min, &max)) ++ return brightness; ++ ++ // Rescale 0..255 to min..max ++ return min + DIV_ROUND_CLOSEST((max - min) * brightness, ++ AMDGPU_MAX_BL_LEVEL); ++} ++ ++static u32 convert_brightness_to_user(const struct amdgpu_dm_backlight_caps *caps, ++ uint32_t brightness) ++{ ++ unsigned min, max; ++ ++ if (!get_brightness_range(caps, &min, &max)) ++ return brightness; ++ ++ if (brightness < min) ++ return 0; ++ // Rescale min..max to 0..255 ++ return DIV_ROUND_CLOSEST(AMDGPU_MAX_BL_LEVEL * (brightness - min), ++ max - min); + } + + static int amdgpu_dm_backlight_update_status(struct backlight_device *bd) +@@ -2941,7 +2940,7 @@ static int amdgpu_dm_backlight_update_status(struct backlight_device *bd) + + link = (struct dc_link *)dm->backlight_link; + +- brightness = convert_brightness(&caps, bd->props.brightness); ++ brightness = convert_brightness_from_user(&caps, bd->props.brightness); + // Change brightness based on AUX property + if (caps.aux_support) + return set_backlight_via_aux(link, brightness); +@@ -2958,7 +2957,7 @@ static int amdgpu_dm_backlight_get_brightness(struct backlight_device *bd) + + if (ret == DC_ERROR_UNEXPECTED) + return bd->props.brightness; +- return ret; ++ return convert_brightness_to_user(&dm->backlight_caps, ret); + } + + static const struct backlight_ops amdgpu_dm_backlight_ops = { + +base-commit: bcf876870b95592b52519ed4aafcf9d95999bc9c +-- +2.26.2 |