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author | Matt Roper <matthew.d.roper@intel.com> | 2018-12-17 14:44:14 -0800 |
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committer | Matt Roper <matthew.d.roper@intel.com> | 2019-01-23 16:29:32 -0800 |
commit | 3c8861d84a4d2c6cd7221d18e49bf9201c6c6115 (patch) | |
tree | 0325843f3a148f53e299e505073fa280c9f9aa9b /drivers/gpu/drm/drm_color_mgmt.c | |
parent | 6e062b60b0b1bd82cac475e63cdb8c451647182b (diff) | |
download | linux-3c8861d84a4d2c6cd7221d18e49bf9201c6c6115.tar.bz2 |
drm: Add color management LUT validation helper (v4)
Some hardware may place additional restrictions on the gamma/degamma
curves described by our LUT properties. E.g., that a gamma curve never
decreases or that the red/green/blue channels of a LUT's entries must be
equal. Let's add a helper function that drivers can use to test that a
userspace-provided LUT is valid and doesn't violate hardware
requirements.
v2:
- Combine into a single helper that just takes a bitmask of the tests
to apply. (Brian Starkey)
- Add additional check (always performed) that LUT property blob size
is always a multiple of the LUT entry size. (stolen from ARM driver)
v3:
- Drop the LUT size check again since
drm_atomic_replace_property_blob_from_id() already covers this for
us. (Alexandru Gheorghe)
v4:
- Use an enum to describe possible test values rather than #define's;
this is cleaner to provide kerneldoc for. (Daniel Vetter)
- s/DRM_COLOR_LUT_INCREASING/DRM_COLOR_LUT_NON_DECREASING/. (Ville)
Cc: Uma Shankar <uma.shankar@intel.com>
Cc: Swati Sharma <swati2.sharma@intel.com>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Reviewed-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe@arm.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181217224415.12848-1-matthew.d.roper@intel.com
Diffstat (limited to 'drivers/gpu/drm/drm_color_mgmt.c')
-rw-r--r-- | drivers/gpu/drm/drm_color_mgmt.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c index 07dcf47daafe..968ca7c91ad8 100644 --- a/drivers/gpu/drm/drm_color_mgmt.c +++ b/drivers/gpu/drm/drm_color_mgmt.c @@ -462,3 +462,47 @@ int drm_plane_create_color_properties(struct drm_plane *plane, return 0; } EXPORT_SYMBOL(drm_plane_create_color_properties); + +/** + * drm_color_lut_check - check validity of lookup table + * @lut: property blob containing LUT to check + * @tests: bitmask of tests to run + * + * Helper to check whether a userspace-provided lookup table is valid and + * satisfies hardware requirements. Drivers pass a bitmask indicating which of + * the tests in &drm_color_lut_tests should be performed. + * + * Returns 0 on success, -EINVAL on failure. + */ +int drm_color_lut_check(struct drm_property_blob *lut, + uint32_t tests) +{ + struct drm_color_lut *entry; + int i; + + if (!lut || !tests) + return 0; + + entry = lut->data; + for (i = 0; i < drm_color_lut_size(lut); i++) { + if (tests & DRM_COLOR_LUT_EQUAL_CHANNELS) { + if (entry[i].red != entry[i].blue || + entry[i].red != entry[i].green) { + DRM_DEBUG_KMS("All LUT entries must have equal r/g/b\n"); + return -EINVAL; + } + } + + if (i > 0 && tests & DRM_COLOR_LUT_NON_DECREASING) { + if (entry[i].red < entry[i - 1].red || + entry[i].green < entry[i - 1].green || + entry[i].blue < entry[i - 1].blue) { + DRM_DEBUG_KMS("LUT entries must never decrease.\n"); + return -EINVAL; + } + } + } + + return 0; +} +EXPORT_SYMBOL(drm_color_lut_check); |