diff options
Diffstat (limited to 'common/recipes-kernel/linux/linux-yocto-4.14.71/4203-drm-amd-display-Fix-regamma-not-affecting-full-inten.patch')
| -rw-r--r-- | common/recipes-kernel/linux/linux-yocto-4.14.71/4203-drm-amd-display-Fix-regamma-not-affecting-full-inten.patch | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/common/recipes-kernel/linux/linux-yocto-4.14.71/4203-drm-amd-display-Fix-regamma-not-affecting-full-inten.patch b/common/recipes-kernel/linux/linux-yocto-4.14.71/4203-drm-amd-display-Fix-regamma-not-affecting-full-inten.patch new file mode 100644 index 00000000..566a23ce --- /dev/null +++ b/common/recipes-kernel/linux/linux-yocto-4.14.71/4203-drm-amd-display-Fix-regamma-not-affecting-full-inten.patch @@ -0,0 +1,66 @@ +From f6c8e652bc51d783469d2c7a59e014b9af0b2396 Mon Sep 17 00:00:00 2001 +From: "Leo (Sunpeng) Li" <sunpeng.li@amd.com> +Date: Tue, 3 Apr 2018 16:07:16 -0400 +Subject: [PATCH 4203/5725] drm/amd/display: Fix regamma not affecting + full-intensity color values + +Hardware understands the regamma LUT as a piecewise linear function, +with points spaced exponentially along the range. We previously +programmed the LUT for range [2^-10, 2^0). This causes (normalized) +color values of 1 (=2^0) to miss the programmed LUT, and fall onto the +end region. + +For DCE, the end region is extrapolated using a single (base, slope) +pair, using the max y-value from the last point in the curve as base. +This presents a problem, since this value affects all three color +channels. Scaling down the intensity of say - the blue regamma curve - +will not affect it's end region. This is especially noticiable when +using RedShift. It scales down the blue and green channels, but leaves +full-intensity colors unshifted. + +Therefore, extend the range to cover [2^-10, 2^1) by programming another +hardware segment, containing only one point. That way, we won't be +hitting the end region. + +Note that things are a bit different for DCN, since the end region can +be set per-channel. + +Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com> +Reviewed-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com> +Acked-by: Harry Wentland <harry.wentland@amd.com> +--- + drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c | 9 ++++++--- + 1 file changed, 6 insertions(+), 3 deletions(-) + +diff --git a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c +index 5bed5a3..b95dd9f 100644 +--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c ++++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c +@@ -456,10 +456,13 @@ dce110_translate_regamma_to_hw_format(const struct dc_transfer_func *output_tf, + + } else { + /* 10 segments +- * segment is from 2^-10 to 2^0 ++ * segment is from 2^-10 to 2^1 ++ * We include an extra segment for range [2^0, 2^1). This is to ++ * ensure that colors with normalized values of 1 don't miss the ++ * LUT. + */ + region_start = -10; +- region_end = 0; ++ region_end = 1; + + seg_distr[0] = 4; + seg_distr[1] = 4; +@@ -471,7 +474,7 @@ dce110_translate_regamma_to_hw_format(const struct dc_transfer_func *output_tf, + seg_distr[7] = 4; + seg_distr[8] = 4; + seg_distr[9] = 4; +- seg_distr[10] = -1; ++ seg_distr[10] = 0; + seg_distr[11] = -1; + seg_distr[12] = -1; + seg_distr[13] = -1; +-- +2.7.4 + |