drm/radeon/kms: don't apply 7xx HDP flush workaround on AGP

It should be required for all 7xx asics, but seems to cause
problems on some AGP 7xx chips.

Fixes:
https://bugzilla.kernel.org/show_bug.cgi?id=19002

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Reported-and-Tested-by: Duncan <1i5t5.duncan@cox.net>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index a322d4f647bd..4d7a2e1bdb90 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -878,12 +878,15 @@ void r600_pcie_gart_tlb_flush(struct radeon_device *rdev)
         u32 tmp;
 
         /* flush hdp cache so updates hit vram */
-        if ((rdev->family >= CHIP_RV770) && (rdev->family <= CHIP_RV740)) {
+        if ((rdev->family >= CHIP_RV770) && (rdev->family <= CHIP_RV740) &&
+            !(rdev->flags & RADEON_IS_AGP)) {
                 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
+                 * This seems to cause problems on some AGP cards. Just use the old
+                 * method for them.
                  */
                 WREG32(HDP_DEBUG1, 0);
                 tmp = readl((void __iomem *)ptr);
@@ -3485,10 +3488,12 @@ int r600_debugfs_mc_info_init(struct radeon_device *rdev)
 void r600_ioctl_wait_idle(struct radeon_device *rdev, struct radeon_bo *bo)
 {
         /* r7xx hw bug.  write to HDP_DEBUG1 followed by fb read
-         * rather than write to HDP_REG_COHERENCY_FLUSH_CNTL
+         * rather than write to HDP_REG_COHERENCY_FLUSH_CNTL.
+         * This seems to cause problems on some AGP cards. Just use the old
+         * method for them.
          */
         if ((rdev->family >= CHIP_RV770) && (rdev->family <= CHIP_RV740) &&
-            rdev->vram_scratch.ptr) {
+            rdev->vram_scratch.ptr && !(rdev->flags & RADEON_IS_AGP)) {
                 void __iomem *ptr = (void *)rdev->vram_scratch.ptr;
                 u32 tmp;