4 files changed, 28 insertions, 3 deletions

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index e1e59e1b318d..28e39bc6768b 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -884,7 +884,17 @@ void r600_pcie_gart_tlb_flush(struct radeon_device *rdev)
         u32 tmp;
 
         /* flush hdp cache so updates hit vram */
-        WREG32(R_005480_HDP_MEM_COHERENCY_FLUSH_CNTL, 0x1);
+        if ((rdev->family >= CHIP_RV770) && (rdev->family <= CHIP_RV740)) {
+                void __iomem *ptr = (void *)rdev->gart.table.vram.ptr;
+                u32 tmp;
+
+                /* r7xx hw bug.  write to HDP_DEBUG1 followed by fb read
+                 * rather than write to HDP_REG_COHERENCY_FLUSH_CNTL
+                 */
+                WREG32(HDP_DEBUG1, 0);
+                tmp = readl((void __iomem *)ptr);
+        } else
+                WREG32(R_005480_HDP_MEM_COHERENCY_FLUSH_CNTL, 0x1);
 
         WREG32(VM_CONTEXT0_INVALIDATION_LOW_ADDR, rdev->mc.gtt_start >> 12);
         WREG32(VM_CONTEXT0_INVALIDATION_HIGH_ADDR, (rdev->mc.gtt_end - 1) >> 12);
@@ -3527,5 +3537,15 @@ int r600_debugfs_mc_info_init(struct radeon_device *rdev)
  */
 void r600_ioctl_wait_idle(struct radeon_device *rdev, struct radeon_bo *bo)
 {
-        WREG32(R_005480_HDP_MEM_COHERENCY_FLUSH_CNTL, 0x1);
+        /* r7xx hw bug.  write to HDP_DEBUG1 followed by fb read
+         * rather than write to HDP_REG_COHERENCY_FLUSH_CNTL
+         */
+        if ((rdev->family >= CHIP_RV770) && (rdev->family <= CHIP_RV740)) {
+                void __iomem *ptr = (void *)rdev->gart.table.vram.ptr;
+                u32 tmp;
+
+                WREG32(HDP_DEBUG1, 0);
+                tmp = readl((void __iomem *)ptr);
+        } else
+                WREG32(R_005480_HDP_MEM_COHERENCY_FLUSH_CNTL, 0x1);
 }
diff --git a/drivers/gpu/drm/radeon/r600d.h b/drivers/gpu/drm/radeon/r600d.h
index b7318ac4f84a..858a1920c0d7 100644
--- a/drivers/gpu/drm/radeon/r600d.h
+++ b/drivers/gpu/drm/radeon/r600d.h
@@ -250,6 +250,7 @@
 #define HDP_NONSURFACE_SIZE                             0x2C0C
 #define HDP_REG_COHERENCY_FLUSH_CNTL                    0x54A0
 #define HDP_TILING_CONFIG                               0x2F3C
+#define HDP_DEBUG1                                      0x2F34
 
 #define MC_VM_AGP_TOP                                   0x2184
 #define MC_VM_AGP_BOT                                   0x2188
diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index 236fe6681922..f1c796810117 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -204,7 +204,10 @@ static void rv770_mc_program(struct radeon_device *rdev)
                 WREG32((0x2c20 + j), 0x00000000);
                 WREG32((0x2c24 + j), 0x00000000);
         }
-        WREG32(HDP_REG_COHERENCY_FLUSH_CNTL, 0);
+        /* r7xx hw bug.  Read from HDP_DEBUG1 rather
+         * than writing to HDP_REG_COHERENCY_FLUSH_CNTL
+         */
+        tmp = RREG32(HDP_DEBUG1);
 
         rv515_mc_stop(rdev, &save);
         if (r600_mc_wait_for_idle(rdev)) {
diff --git a/drivers/gpu/drm/radeon/rv770d.h b/drivers/gpu/drm/radeon/rv770d.h
index fd733f268e3d..b7a5a20e81dc 100644
--- a/drivers/gpu/drm/radeon/rv770d.h
+++ b/drivers/gpu/drm/radeon/rv770d.h
@@ -133,6 +133,7 @@
 #define HDP_NONSURFACE_SIZE                             0x2C0C
 #define HDP_REG_COHERENCY_FLUSH_CNTL                    0x54A0
 #define HDP_TILING_CONFIG                               0x2F3C
+#define HDP_DEBUG1                                      0x2F34
 
 #define MC_SHARED_CHMAP                                         0x2004
 #define         NOOFCHAN_SHIFT                                  12