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authorDaniel Vetter <daniel.vetter@ffwll.ch>2016-09-26 12:04:37 +0300
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-11-16 00:39:48 +0300
commit717fd813b8130e36971205af09b0e6a5e6d3c433 (patch)
tree03c8af9fcff2271982f2ef5154975a743a2a4963 /drivers
parentedd420eaffb3a618ddc8740683abc039ad97237f (diff)
downloadlinux-717fd813b8130e36971205af09b0e6a5e6d3c433.tar.xz
drm/color: document NULL values and default settings better
Brought up in a discussion for enabling gamma on fsl-dcu. Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Meng Yi <meng.yi@nxp.com> Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20160926090437.22676-1-daniel.vetter@ffwll.ch
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpu/drm/drm_color_mgmt.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index d28ffdd2b929..6543ebde501a 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -41,6 +41,10 @@
* nor use all the elements of the LUT (for example the hardware might
* choose to interpolate between LUT[0] and LUT[4]).
*
+ * Setting this to NULL (blob property value set to 0) means a
+ * linear/pass-thru gamma table should be used. This is generally the
+ * driver boot-up state too.
+ *
* “DEGAMMA_LUT_SIZE”:
* Unsinged range property to give the size of the lookup table to be set
* on the DEGAMMA_LUT property (the size depends on the underlying
@@ -54,6 +58,10 @@
* lookup through the gamma LUT. The data is interpreted as a struct
* &drm_color_ctm.
*
+ * Setting this to NULL (blob property value set to 0) means a
+ * unit/pass-thru matrix should be used. This is generally the driver
+ * boot-up state too.
+ *
* “GAMMA_LUT”:
* Blob property to set the gamma lookup table (LUT) mapping pixel data
* after the transformation matrix to data sent to the connector. The
@@ -62,6 +70,10 @@
* nor use all the elements of the LUT (for example the hardware might
* choose to interpolate between LUT[0] and LUT[4]).
*
+ * Setting this to NULL (blob property value set to 0) means a
+ * linear/pass-thru gamma table should be used. This is generally the
+ * driver boot-up state too.
+ *
* “GAMMA_LUT_SIZE”:
* Unsigned range property to give the size of the lookup table to be set
* on the GAMMA_LUT property (the size depends on the underlying hardware).