drm/radeon: Don't read from CP ring write pointer registers.

Apparently this doesn't always work reliably, e.g. at resume time.

Just initialize to 0, so the ring is considered empty.

Tested with hibernation on Sumo and Cayman cards.

Should fix https://bugs.launchpad.net/ubuntu/+source/linux/+bug/820746/ .

Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

4 files changed, 12 insertions, 14 deletions

diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index dc0a5b56c81..f10d1c1c255 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -1404,7 +1404,8 @@ int evergreen_cp_resume(struct radeon_device *rdev)
         /* Initialize the ring buffer's read and write pointers */
         WREG32(CP_RB_CNTL, tmp | RB_RPTR_WR_ENA);
         WREG32(CP_RB_RPTR_WR, 0);
-        WREG32(CP_RB_WPTR, 0);
+        rdev->cp.wptr = 0;
+        WREG32(CP_RB_WPTR, rdev->cp.wptr);
 
         /* set the wb address wether it's enabled or not */
         WREG32(CP_RB_RPTR_ADDR,
@@ -1426,7 +1427,6 @@ int evergreen_cp_resume(struct radeon_device *rdev)
         WREG32(CP_DEBUG, (1 << 27) | (1 << 28));
 
         rdev->cp.rptr = RREG32(CP_RB_RPTR);
-        rdev->cp.wptr = RREG32(CP_RB_WPTR);
 
         evergreen_cp_start(rdev);
         rdev->cp.ready = true;
diff --git a/drivers/gpu/drm/radeon/ni.c b/drivers/gpu/drm/radeon/ni.c
index cbf57d75d92..99fbd793c08 100644
--- a/drivers/gpu/drm/radeon/ni.c
+++ b/drivers/gpu/drm/radeon/ni.c
@@ -1187,7 +1187,8 @@ int cayman_cp_resume(struct radeon_device *rdev)
 
         /* Initialize the ring buffer's read and write pointers */
         WREG32(CP_RB0_CNTL, tmp | RB_RPTR_WR_ENA);
-        WREG32(CP_RB0_WPTR, 0);
+        rdev->cp.wptr = 0;
+        WREG32(CP_RB0_WPTR, rdev->cp.wptr);
 
         /* set the wb address wether it's enabled or not */
         WREG32(CP_RB0_RPTR_ADDR, (rdev->wb.gpu_addr + RADEON_WB_CP_RPTR_OFFSET) & 0xFFFFFFFC);
@@ -1207,7 +1208,6 @@ int cayman_cp_resume(struct radeon_device *rdev)
         WREG32(CP_RB0_BASE, rdev->cp.gpu_addr >> 8);
 
         rdev->cp.rptr = RREG32(CP_RB0_RPTR);
-        rdev->cp.wptr = RREG32(CP_RB0_WPTR);
 
         /* ring1  - compute only */
         /* Set ring buffer size */
@@ -1220,7 +1220,8 @@ int cayman_cp_resume(struct radeon_device *rdev)
 
         /* Initialize the ring buffer's read and write pointers */
         WREG32(CP_RB1_CNTL, tmp | RB_RPTR_WR_ENA);
-        WREG32(CP_RB1_WPTR, 0);
+        rdev->cp1.wptr = 0;
+        WREG32(CP_RB1_WPTR, rdev->cp1.wptr);
 
         /* set the wb address wether it's enabled or not */
         WREG32(CP_RB1_RPTR_ADDR, (rdev->wb.gpu_addr + RADEON_WB_CP1_RPTR_OFFSET) & 0xFFFFFFFC);
@@ -1232,7 +1233,6 @@ int cayman_cp_resume(struct radeon_device *rdev)
         WREG32(CP_RB1_BASE, rdev->cp1.gpu_addr >> 8);
 
         rdev->cp1.rptr = RREG32(CP_RB1_RPTR);
-        rdev->cp1.wptr = RREG32(CP_RB1_WPTR);
 
         /* ring2 - compute only */
         /* Set ring buffer size */
@@ -1245,7 +1245,8 @@ int cayman_cp_resume(struct radeon_device *rdev)
 
         /* Initialize the ring buffer's read and write pointers */
         WREG32(CP_RB2_CNTL, tmp | RB_RPTR_WR_ENA);
-        WREG32(CP_RB2_WPTR, 0);
+        rdev->cp2.wptr = 0;
+        WREG32(CP_RB2_WPTR, rdev->cp2.wptr);
 
         /* set the wb address wether it's enabled or not */
         WREG32(CP_RB2_RPTR_ADDR, (rdev->wb.gpu_addr + RADEON_WB_CP2_RPTR_OFFSET) & 0xFFFFFFFC);
@@ -1257,7 +1258,6 @@ int cayman_cp_resume(struct radeon_device *rdev)
         WREG32(CP_RB2_BASE, rdev->cp2.gpu_addr >> 8);
 
         rdev->cp2.rptr = RREG32(CP_RB2_RPTR);
-        rdev->cp2.wptr = RREG32(CP_RB2_WPTR);
 
         /* start the rings */
         cayman_cp_start(rdev);
diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index f2204cb1ccd..11e44a3479e 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -990,7 +990,8 @@ int r100_cp_init(struct radeon_device *rdev, unsigned ring_size)
         /* Force read & write ptr to 0 */
         WREG32(RADEON_CP_RB_CNTL, tmp | RADEON_RB_RPTR_WR_ENA | RADEON_RB_NO_UPDATE);
         WREG32(RADEON_CP_RB_RPTR_WR, 0);
-        WREG32(RADEON_CP_RB_WPTR, 0);
+        rdev->cp.wptr = 0;
+        WREG32(RADEON_CP_RB_WPTR, rdev->cp.wptr);
 
         /* set the wb address whether it's enabled or not */
         WREG32(R_00070C_CP_RB_RPTR_ADDR,
@@ -1007,9 +1008,6 @@ int r100_cp_init(struct radeon_device *rdev, unsigned ring_size)
         WREG32(RADEON_CP_RB_CNTL, tmp);
         udelay(10);
         rdev->cp.rptr = RREG32(RADEON_CP_RB_RPTR);
-        rdev->cp.wptr = RREG32(RADEON_CP_RB_WPTR);
-        /* protect against crazy HW on resume */
-        rdev->cp.wptr &= rdev->cp.ptr_mask;
         /* Set cp mode to bus mastering & enable cp*/
         WREG32(RADEON_CP_CSQ_MODE,
                REG_SET(RADEON_INDIRECT2_START, indirect2_start) |
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index aa5571b73aa..c68427612e3 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -2209,7 +2209,8 @@ int r600_cp_resume(struct radeon_device *rdev)
         /* Initialize the ring buffer's read and write pointers */
         WREG32(CP_RB_CNTL, tmp | RB_RPTR_WR_ENA);
         WREG32(CP_RB_RPTR_WR, 0);
-        WREG32(CP_RB_WPTR, 0);
+        rdev->cp.wptr = 0;
+        WREG32(CP_RB_WPTR, rdev->cp.wptr);
 
         /* set the wb address whether it's enabled or not */
         WREG32(CP_RB_RPTR_ADDR,
@@ -2231,7 +2232,6 @@ int r600_cp_resume(struct radeon_device *rdev)
         WREG32(CP_DEBUG, (1 << 27) | (1 << 28));
 
         rdev->cp.rptr = RREG32(CP_RB_RPTR);
-        rdev->cp.wptr = RREG32(CP_RB_WPTR);
 
         r600_cp_start(rdev);
         rdev->cp.ready = true;