drm/core: Change declaration for gamma_set.

Change return value to int to propagate errors from gamma_set,
and remove start parameter. Updates always use the full size,
and some drivers even ignore the start parameter altogether.

This is needed for atomic drivers, where an atomic commit can
fail with -EINTR or -ENOMEM and should be restarted. This is already
and issue for drm_atomic_helper_legacy_set_gamma, which this patch
fixes up.

Changes since v1:
- Fix compiler warning. (Emil)
- Fix commit message (Daniel)

Cc: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Mathieu Larouche <mathieu.larouche@matrox.com>
Cc: Thierry Reding <treding@nvidia.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[danvet: Improve commit message a bit more, mention that this fixes
the helper.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/742944bc-9f41-1acb-df4f-0fd4c8a10168@linux.intel.com

2 files changed, 12 insertions, 9 deletions

diff --git a/drivers/gpu/drm/nouveau/dispnv04/crtc.c b/drivers/gpu/drm/nouveau/dispnv04/crtc.c
index 6f318c54da33..0cb7a18cde26 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/crtc.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/crtc.c
@@ -785,14 +785,14 @@ nv_crtc_disable(struct drm_crtc *crtc)
 	nouveau_bo_ref(NULL, &disp->image[nv_crtc->index]);
 }
 
-static void
-nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, uint32_t start,
+static int
+nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
 		  uint32_t size)
 {
-	int end = (start + size > 256) ? 256 : start + size, i;
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
+	int i;
 
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		nv_crtc->lut.r[i] = r[i];
 		nv_crtc->lut.g[i] = g[i];
 		nv_crtc->lut.b[i] = b[i];
@@ -805,10 +805,12 @@ nv_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, uint32_t start,
 	 */
 	if (!nv_crtc->base.primary->fb) {
 		nv_crtc->lut.depth = 0;
-		return;
+		return 0;
 	}
 
 	nv_crtc_gamma_load(crtc);
+
+	return 0;
 }
 
 static int
diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
index 3ffc2b0057bf..7a7788212df7 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -1346,21 +1346,22 @@ nv50_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
 	return 0;
 }
 
-static void
+static int
 nv50_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
-		    uint32_t start, uint32_t size)
+		    uint32_t size)
 {
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
-	u32 end = min_t(u32, start + size, 256);
 	u32 i;
 
-	for (i = start; i < end; i++) {
+	for (i = 0; i < size; i++) {
 		nv_crtc->lut.r[i] = r[i];
 		nv_crtc->lut.g[i] = g[i];
 		nv_crtc->lut.b[i] = b[i];
 	}
 
 	nv50_crtc_lut_load(crtc);
+
+	return 0;
 }
 
 static void