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-rw-r--r--shared-core/radeon_cp.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/shared-core/radeon_cp.c b/shared-core/radeon_cp.c
index f579e01a..0200797a 100644
--- a/shared-core/radeon_cp.c
+++ b/shared-core/radeon_cp.c
@@ -825,7 +825,7 @@ static void radeon_cp_init_ring_buffer(struct drm_device * dev,
static void radeon_test_writeback(drm_radeon_private_t * dev_priv)
{
- u32 tmp;
+ u32 tmp, scratch1_store;
void *ring_read_ptr;
if (dev_priv->mm.ring_read.bo)
@@ -833,6 +833,7 @@ static void radeon_test_writeback(drm_radeon_private_t * dev_priv)
else
ring_read_ptr = dev_priv->ring_rptr->handle;
+ scratch1_store = RADEON_READ(RADEON_SCRATCH_REG1);
/* Writeback doesn't seem to work everywhere, test it here and possibly
* enable it if it appears to work
*/
@@ -858,6 +859,9 @@ static void radeon_test_writeback(drm_radeon_private_t * dev_priv)
DRM_INFO("writeback forced off\n");
}
+ /* write back previous value */
+ RADEON_WRITE(RADEON_SCRATCH_REG1, scratch1_store);
+
if (!dev_priv->writeback_works) {
/* Disable writeback to avoid unnecessary bus master transfers */
RADEON_WRITE(RADEON_CP_RB_CNTL, RADEON_READ(RADEON_CP_RB_CNTL) | RADEON_RB_NO_UPDATE);
@@ -2353,6 +2357,8 @@ int radeon_modeset_cp_resume(struct drm_device *dev)
radeon_do_engine_reset(dev);
+ radeon_test_writeback(dev_priv);
+
radeon_do_cp_start(dev_priv);
return 0;
}