drm/radeon/kms: fix a regression on r7xx AGP due to the HDP flush fix

commit: 812d046915f48236657f02c06d7dc47140e9ceda
drm/radeon/kms/r7xx: add workaround for hw issue with HDP flush
breaks on AGP boards since there is no VRAM gart table.

This patch fixes the issue by creating a VRAM scratch page so that
can be used on both AGP and PCIE.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=29834

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index f1c796810117..a84e38643788 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -905,6 +905,54 @@ static void rv770_gpu_init(struct radeon_device *rdev)
 
 }
 
+static int rv770_vram_scratch_init(struct radeon_device *rdev)
+{
+	int r;
+	u64 gpu_addr;
+
+	if (rdev->vram_scratch.robj == NULL) {
+		r = radeon_bo_create(rdev, NULL, RADEON_GPU_PAGE_SIZE,
+					true, RADEON_GEM_DOMAIN_VRAM,
+					&rdev->vram_scratch.robj);
+		if (r) {
+			return r;
+		}
+	}
+
+	r = radeon_bo_reserve(rdev->vram_scratch.robj, false);
+	if (unlikely(r != 0))
+		return r;
+	r = radeon_bo_pin(rdev->vram_scratch.robj,
+			  RADEON_GEM_DOMAIN_VRAM, &gpu_addr);
+	if (r) {
+		radeon_bo_unreserve(rdev->vram_scratch.robj);
+		return r;
+	}
+	r = radeon_bo_kmap(rdev->vram_scratch.robj,
+				(void **)&rdev->vram_scratch.ptr);
+	if (r)
+		radeon_bo_unpin(rdev->vram_scratch.robj);
+	radeon_bo_unreserve(rdev->vram_scratch.robj);
+
+	return r;
+}
+
+static void rv770_vram_scratch_fini(struct radeon_device *rdev)
+{
+	int r;
+
+	if (rdev->vram_scratch.robj == NULL) {
+		return;
+	}
+	r = radeon_bo_reserve(rdev->vram_scratch.robj, false);
+	if (likely(r == 0)) {
+		radeon_bo_kunmap(rdev->vram_scratch.robj);
+		radeon_bo_unpin(rdev->vram_scratch.robj);
+		radeon_bo_unreserve(rdev->vram_scratch.robj);
+	}
+	radeon_bo_unref(&rdev->vram_scratch.robj);
+}
+
 int rv770_mc_init(struct radeon_device *rdev)
 {
 	u32 tmp;
@@ -970,6 +1018,9 @@ static int rv770_startup(struct radeon_device *rdev)
 		if (r)
 			return r;
 	}
+	r = rv770_vram_scratch_init(rdev);
+	if (r)
+		return r;
 	rv770_gpu_init(rdev);
 	r = r600_blit_init(rdev);
 	if (r) {
@@ -1195,6 +1246,7 @@ void rv770_fini(struct radeon_device *rdev)
 	r600_irq_fini(rdev);
 	radeon_irq_kms_fini(rdev);
 	rv770_pcie_gart_fini(rdev);
+	rv770_vram_scratch_fini(rdev);
 	radeon_gem_fini(rdev);
 	radeon_fence_driver_fini(rdev);
 	radeon_clocks_fini(rdev);