drm: expand gamma_set

Expand the crtc_gamma_set function to accept a starting offset. The
reason for this is to eventually use this function for setcolreg from
drm_fb_helper.c. The fbdev colormap function can start at any offset in
the color map.

Signed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 6130ec9ed502..5764f4d3b4f1 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -161,17 +161,13 @@ void radeon_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 *green,
 }
 
 static void radeon_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green,
-                                  u16 *blue, uint32_t size)
+                                  u16 *blue, uint32_t start, uint32_t size)
 {
         struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
-        int i;
-
-        if (size != 256) {
-                return;
-        }
+        int end = (start + size > 256) ? 256 : start + size, i;
 
         /* userspace palettes are always correct as is */
-        for (i = 0; i < 256; i++) {
+        for (i = start; i < end; i++) {
                 radeon_crtc->lut_r[i] = red[i] >> 6;
                 radeon_crtc->lut_g[i] = green[i] >> 6;
                 radeon_crtc->lut_b[i] = blue[i] >> 6;