drm: Make the CRTC gamma_set operation optional
Drivers for hardware without gamma support should not be forced to
implement a no-op gamma set operation.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Rob Clark <rob.clark@linaro.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 404597e..6cb47d9 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3332,6 +3332,11 @@
}
crtc = obj_to_crtc(obj);
+ if (crtc->funcs->gamma_set == NULL) {
+ ret = -ENOSYS;
+ goto out;
+ }
+
/* memcpy into gamma store */
if (crtc_lut->gamma_size != crtc->gamma_size) {
ret = -EINVAL;
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 9b773d5..5683b7f 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -136,6 +136,9 @@
{
uint16_t *r_base, *g_base, *b_base;
+ if (crtc->funcs->gamma_set == NULL)
+ return;
+
r_base = crtc->gamma_store;
g_base = r_base + crtc->gamma_size;
b_base = g_base + crtc->gamma_size;