drm/radeon: some r420s have a CP race with the DMA engine.
This patch makes sure the CP doesn't DMA do VRAM while 2D
is active by inserting a CP resync token.
todo: port to kms.
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_cp.c b/drivers/gpu/drm/radeon/radeon_cp.c
index fa063d0..4f7afc7 100644
--- a/drivers/gpu/drm/radeon/radeon_cp.c
+++ b/drivers/gpu/drm/radeon/radeon_cp.c
@@ -616,6 +616,18 @@
dev_priv->cp_running = 1;
+ /* on r420, any DMA from CP to system memory while 2D is active
+ * can cause a hang. workaround is to queue a CP RESYNC token
+ */
+ if ((dev_priv->flags & RADEON_FAMILY_MASK) == CHIP_R420) {
+ BEGIN_RING(3);
+ OUT_RING(CP_PACKET0(R300_CP_RESYNC_ADDR, 1));
+ OUT_RING(5); /* scratch reg 5 */
+ OUT_RING(0xdeadbeef);
+ ADVANCE_RING();
+ COMMIT_RING();
+ }
+
BEGIN_RING(8);
/* isync can only be written through cp on r5xx write it here */
OUT_RING(CP_PACKET0(RADEON_ISYNC_CNTL, 0));
@@ -653,8 +665,19 @@
*/
static void radeon_do_cp_stop(drm_radeon_private_t * dev_priv)
{
+ RING_LOCALS;
DRM_DEBUG("\n");
+ /* finish the pending CP_RESYNC token */
+ if ((dev_priv->flags & RADEON_FAMILY_MASK) == CHIP_R420) {
+ BEGIN_RING(2);
+ OUT_RING(CP_PACKET0(R300_RB3D_DSTCACHE_CTLSTAT, 0));
+ OUT_RING(R300_RB3D_DC_FINISH);
+ ADVANCE_RING();
+ COMMIT_RING();
+ radeon_do_wait_for_idle(dev_priv);
+ }
+
RADEON_WRITE(RADEON_CP_CSQ_CNTL, RADEON_CSQ_PRIDIS_INDDIS);
dev_priv->cp_running = 0;