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path: root/include/drm/drm_color_mgmt.h
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2025-11-26drm: Add helper to extract lut from struct drm_color_lut32Chaitanya Kumar Borah
Add helper to extract lut values in 32-bit precision needed by hardware. Signed-off-by: Alex Hung <alex.hung@amd.com> Signed-off-by: Uma Shankar <uma.shankar@intel.com> Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> Reviewed-by: Sebastian Wick <sebastian.wick@redhat.com> Signed-off-by: Simon Ser <contact@emersion.fr> Link: https://patch.msgid.link/20251115000237.3561250-37-alex.hung@amd.com
2025-11-26drm: Add Enhanced LUT precision structureUma Shankar
Existing LUT precision structure drm_color_lut has only 16 bit precision. This is not enough for upcoming enhanced hardwares and advance usecases like HDR processing. Hence added a new structure with 32 bit precision values. Signed-off-by: Alex Hung <alex.hung@amd.com> Signed-off-by: Uma Shankar <uma.shankar@intel.com> Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> Reviewed-by: Sebastian Wick <sebastian.wick@redhat.com> Signed-off-by: Simon Ser <contact@emersion.fr> Link: https://patch.msgid.link/20251115000237.3561250-36-alex.hung@amd.com
2025-08-26drm/color-mgmt: Prepare for RGB332 palettesThomas Zimmermann
Add helper drm_crtc_fill_palette_332(), which fills palettes with RGB332 color data. Each color in RGB332 format serves as an index into an 8-bit palette that stores the corresponding component-based colors. Vesadrm will use the new helper to emulate RGB formats on top of framebuffers in C8 format. v2: - add comments on bit operations (Javier) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Link: https://lore.kernel.org/r/20250714151513.309475-6-tzimmermann@suse.de
2025-05-26drm: Add helpers for programming hardware gamma LUTsThomas Zimmermann
Provide helpers that program hardware gamma LUTs. Tha gamma ramp is either provided by the driver or generated by the helper. The DRM driver exports the GAMMA_LUT property with a fixed number of entries per color component, such as 256 on 8-bit-wide components. The entries describe the gamma ramp of each individual component. The new helper drm_crtc_load_gamma_888() loads such gamma ramp to hardware. The hardware uses each displayed pixel's individial components as indices into the hardware gamma table. For color modes with less than 8 bits per color component, the helpers drm_crtc_load_gamma_565_from() and drm_crtc_load_gamma_555_from_888() interpolate the provided gamma ramp to reduce it to the correct number of entries; 5/6/5 for RGB565-like formats and 5/5/5 for XRGB1555-like formats. If no gamma ramp has been provided, drivers can use the new helper drm_crtc_fill_gamma_888() to load a default gamma ramp with 256 entries per color component. For color modes with less bits, the new helpers drm_crtc_fill_gamma_565() and drm_crtc_fill_gamma_555() are available. The default gamma ramp uses a gamma factor of 1. For color modes with palette, drm_crtc_load_palette_8() load an 8-bit palette into the hardware. If no palette has been specified, drm_crtc_fill_palette_8() load a system-specific default palette. This is currently only a grey-scale palette with increasing luminance, but later patches can change this. For PCs, a VGA default palette could be used. v2: - drop comment on gamma factor of 2.2 (Michel, Pekka) - fix typos in commit description (Javier) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Acked-by: Javier Martinez Canillas <javierm@redhat.com> Link: https://lore.kernel.org/r/20250520094203.30545-2-tzimmermann@suse.de
2023-12-19drm: using mul_u32_u32() requires linux/math64.hStephen Rothwell
Some pending include file cleanups produced this error: In file included from include/linux/kernel.h:27, from drivers/gpu/ipu-v3/ipu-dp.c:7: include/drm/drm_color_mgmt.h: In function 'drm_color_lut_extract': include/drm/drm_color_mgmt.h:45:46: error: implicit declaration of function 'mul_u32_u32' [-Werror=implicit-function-declaration] 45 | return DIV_ROUND_CLOSEST_ULL(mul_u32_u32(user_input, (1 << bit_precision) - 1), | ^~~~~~~~~~~ Fixes: c6fbb6bca108 ("drm: Fix color LUT rounding") Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20231219145734.13e40e1e@canb.auug.org.au
2023-11-23drm: Fix color LUT roundingVille Syrjälä
The current implementation of drm_color_lut_extract() generates weird results. Eg. if we go through all the values for 16->8bpc conversion we see the following pattern: in out (count) 0 - 7f -> 0 (128) 80 - 17f -> 1 (256) 180 - 27f -> 2 (256) 280 - 37f -> 3 (256) ... fb80 - fc7f -> fc (256) fc80 - fd7f -> fd (256) fd80 - fe7f -> fe (256) fe80 - ffff -> ff (384) So less values map to 0 and more values map 0xff, which doesn't seem particularly great. To get just the same number of input values to map to the same output values we'd just need to drop the rounding entrirely. But perhaps a better idea would be to follow the OpenGL int<->float conversion rules, in which case we get the following results: in out (count) 0 - 80 -> 0 (129) 81 - 181 -> 1 (257) 182 - 282 -> 2 (257) 283 - 383 -> 3 (257) ... fc7c - fd7c -> fc (257) fd7d - fe7d -> fd (257) fe7e - ff7e -> fe (257) ff7f - ffff -> ff (129) Note that since the divisor is constant the compiler is able to optimize away the integer division in most cases. The only exception is the _ULL() case on 32bit architectures since that gets emitted as inline asm via do_div() and thus the compiler doesn't get to optimize it. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20231013131402.24072-2-ville.syrjala@linux.intel.com Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Acked-by: Maxime Ripard <mripard@kernel.org>
2019-11-29drm: Inline drm_color_lut_extract()Ville Syrjälä
This thing can get called several thousand times per LUT so seems like we want to inline it to: - avoid the function call overhead - allow constant folding A quick synthetic test (w/o any hardware interaction) with a ridiculously large LUT size shows about 50% reduction in runtime on my HSW and BSW boxes. Slightly less with more reasonable LUT size but still easily measurable in tens of microseconds. v2: Include drm_color_mgmt.h in the .rst (Daniel) Cc: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191108135654.12907-1-ville.syrjala@linux.intel.com
2019-11-14drm: Add a new helper drm_color_ctm_s31_32_to_qm_n()james qian wang (Arm Technology China)
Add a new helper function drm_color_ctm_s31_32_to_qm_n() for driver to convert S31.32 sign-magnitude to Qm.n 2's complement that supported by hardware. V4: Address Mihai, Daniel and Ilia's review comments. V5: Includes the sign bit in the value of m (Qm.n). V6: Allows m = 0 according to Mihail's comments. V7: Address Mihail's comments. V8: Use type 'u32' to replace 'uint32_t' V9: Rebase. Signed-off-by: james qian wang (Arm Technology China) <james.qian.wang@arm.com> Reviewed-by: Mihail Atanassov <mihail.atanassov@arm.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20191112110927.20931-2-james.qian.wang@arm.com
2019-01-29drm: Constify drm_color_lut_check()Ville Syrjälä
drm_color_lut_check() doens't modify the passed in blob so let's make it const. Also s/uint32_t/u32/ while at it. v2: Reduce line wraps (Sam) Cc: Matt Roper <matthew.d.roper@intel.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190129170609.5718-1-ville.syrjala@linux.intel.com Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2019-01-23drm: Add color management LUT validation helper (v4)Matt Roper
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
2018-09-09drm: drop drmP.h include from drm_plane.cDaniel Vetter
Just a bit of missing includes and pre declarations. v2: Compiles now, with drm/drm_util.h extracted. v3: Rebase v3: Fix up commit message (Sam Ravnborg) Reviewed-by: Sean Paul <seanpaul@chromium.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180905135711.28370-3-daniel.vetter@ffwll.ch
2018-03-16drm: Introduce drm_color_lut_size()Ville Syrjälä
Provide a small helper to convert the blob length in bytes to the number of LUT entries. v2: Add kerneldoc (Daniel) Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20180315152338.7248-1-ville.syrjala@linux.intel.com
2018-03-02drm: Add optional COLOR_ENCODING and COLOR_RANGE properties to drm_planeJyri Sarha
Add a standard optional properties to support different non RGB color encodings in DRM planes. COLOR_ENCODING select the supported non RGB color encoding, for instance ITU-R BT.709 YCbCr. COLOR_RANGE selects the value ranges within the selected color encoding. The properties are stored to drm_plane object to allow different set of supported encoding for different planes on the device. v2: Add/fix kerneldocs, verify bitmasks (danvet) Cc: Harry Wentland <harry.wentland@amd.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Daniel Stone <daniel@fooishbar.org> Cc: Russell King - ARM Linux <linux@armlinux.org.uk> Cc: Ilia Mirkin <imirkin@alum.mit.edu> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Uma Shankar <uma.shankar@intel.com> Cc: Shashank Sharma <shashank.sharma@intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Jyri Sarha <jsarha@ti.com> [vsyrjala v2: Add/fix kerneldocs, verify bitmasks] Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180219202823.10508-1-ville.syrjala@linux.intel.com Acked-by: Harry Wentland <harry.wentland@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2017-05-02drm: drm_color_mgmt.h needs struct drm_crtc declarationJyri Sarha
Signed-off-by: Jyri Sarha <jsarha@ti.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/69c913b3ae3fc7235c059e08f58fb0a172d98cf8.1492768073.git.jsarha@ti.com
2017-01-31drm/color: un-inline drm_color_lut_extract()Jani Nikula
The function is not that big, but it's also not used for anything performance critical. Make it a normal function. As a side effect, this apparently makes sparse smarter about what it's doing, and gets rid of the warning: ./include/drm/drm_color_mgmt.h:53:28: warning: shift too big (4294967295) for type unsigned long ./include/drm/drm_color_mgmt.h:53:28: warning: cast truncates bits from constant value (8000000000000000 becomes 0) v2: rebased Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1485531291-24821-1-git-send-email-jani.nikula@intel.com
2017-01-25drm/kms-core: Use recommened kerneldoc for struct member refsDaniel Vetter
I just learned that &struct_name.member_name works and looks pretty even. It doesn't (yet) link to the member directly though, which would be really good for big structures or vfunc tables (where the per-member kerneldoc tends to be long). Also some minor drive-by polish where it makes sense, I read a lot of docs ... v2: Review from Eric. Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170125062657.19270-4-daniel.vetter@ffwll.ch
2016-09-22drm/doc: Document color space handlingDaniel Vetter
Again move it from the unmaintainable csv into DOC free-form overview sections. v2: Types Lionel&Sean spotted. Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Reviewed-by: Sean Paul <seanpaul@chromium.org> Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: http://patchwork.freedesktop.org/patch/msgid/1474448370-32227-6-git-send-email-daniel.vetter@ffwll.ch
2016-09-22drm: Extract drm_color_mgmt.[hc]Daniel Vetter
For both the new degamm/lut/gamma atomic combo, and the old legacy gamma tables. Acked-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: http://patchwork.freedesktop.org/patch/msgid/1474448370-32227-5-git-send-email-daniel.vetter@ffwll.ch