drm/radeon: Set MASTER_UPDATE_MODE to 0 again

With the previous change, it's safe to let page flips take effect
anytime during a vertical blank period.

This can avoid delaying a flip by a frame in some cases where we get to
radeon_flip_work_func -> adev->mode_info.funcs->page_flip during a
vertical blank period.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/atombios_crtc.c

@@ -1433,8 +1433,8 @@ static int dce4_crtc_do_set_base(struct drm_crtc *crtc,
 	WREG32(EVERGREEN_VIEWPORT_SIZE + radeon_crtc->crtc_offset,
 	       (viewport_w << 16) | viewport_h);
 
-	/* set pageflip to happen only at start of vblank interval (front porch) */
-	WREG32(EVERGREEN_MASTER_UPDATE_MODE + radeon_crtc->crtc_offset, 3);
+	/* set pageflip to happen anywhere in vblank interval */
+	WREG32(EVERGREEN_MASTER_UPDATE_MODE + radeon_crtc->crtc_offset, 0);
 
 	if (!atomic && fb && fb != crtc->primary->fb) {
 		radeon_fb = to_radeon_framebuffer(fb);
@@ -1632,8 +1632,8 @@ static int avivo_crtc_do_set_base(struct drm_crtc *crtc,
 	WREG32(AVIVO_D1MODE_VIEWPORT_SIZE + radeon_crtc->crtc_offset,
 	       (viewport_w << 16) | viewport_h);
 
-	/* set pageflip to happen only at start of vblank interval (front porch) */
-	WREG32(AVIVO_D1MODE_MASTER_UPDATE_MODE + radeon_crtc->crtc_offset, 3);
+	/* set pageflip to happen anywhere in vblank interval */
+	WREG32(AVIVO_D1MODE_MASTER_UPDATE_MODE + radeon_crtc->crtc_offset, 0);
 
 	if (!atomic && fb && fb != crtc->primary->fb) {
 		radeon_fb = to_radeon_framebuffer(fb);

drivers/gpu/drm/radeon/evergreen.c

@@ -2878,9 +2878,8 @@ void evergreen_mc_resume(struct radeon_device *rdev, struct evergreen_mc_save *s
 	for (i = 0; i < rdev->num_crtc; i++) {
 		if (save->crtc_enabled[i]) {
 			tmp = RREG32(EVERGREEN_MASTER_UPDATE_MODE + crtc_offsets[i]);
-			if ((tmp & 0x7) != 3) {
+			if ((tmp & 0x7) != 0) {
 				tmp &= ~0x7;
-				tmp |= 0x3;
 				WREG32(EVERGREEN_MASTER_UPDATE_MODE + crtc_offsets[i], tmp);
 			}
 			tmp = RREG32(EVERGREEN_GRPH_UPDATE + crtc_offsets[i]);

drivers/gpu/drm/radeon/rv515.c

@@ -406,9 +406,8 @@ void rv515_mc_resume(struct radeon_device *rdev, struct rv515_mc_save *save)
 	for (i = 0; i < rdev->num_crtc; i++) {
 		if (save->crtc_enabled[i]) {
 			tmp = RREG32(AVIVO_D1MODE_MASTER_UPDATE_MODE + crtc_offsets[i]);
-			if ((tmp & 0x7) != 3) {
+			if ((tmp & 0x7) != 0) {
 				tmp &= ~0x7;
-				tmp |= 0x3;
 				WREG32(AVIVO_D1MODE_MASTER_UPDATE_MODE + crtc_offsets[i], tmp);
 			}
 			tmp = RREG32(AVIVO_D1GRPH_UPDATE + crtc_offsets[i]);