[PATCH] drm/radeon: Fix screen corruption

[Luben Tuikov]

Fix screen corruption on older 32-bit systems using AGP chips. Partially
revert commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713.

Cc: Mikhail Krylov <sqarert at gmail.com>
Cc: Alex Deucher <Alexander.Deucher at amd.com>
Cc: Robin Murphy <robin.murphy at arm.com>
Cc: Direct Rendering Infrastructure - Development <dri-devel at lists.freedesktop.org>
Cc: AMD Graphics <amd-gfx at lists.freedesktop.org>
Fixes: 33b3ad3788aba8 ("drm/radeon: handle PCIe root ports with addressing limitations")
Signed-off-by: Luben Tuikov <luben.tuikov at amd.com>
---
 drivers/gpu/drm/radeon/radeon.h        | 1 +
 drivers/gpu/drm/radeon/radeon_device.c | 2 +-
 drivers/gpu/drm/radeon/radeon_ttm.c    | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 37dec92339b16a..4fe38fd9be3267 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -2426,6 +2426,7 @@ struct radeon_device {
 	struct radeon_wb		wb;
 	struct radeon_dummy_page	dummy_page;
 	bool				shutdown;
+	bool                            need_dma32;
 	bool				need_swiotlb;
 	bool				accel_working;
 	bool				fastfb_working; /* IGP feature*/
diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 6344454a772172..3643a3cfe061bd 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1370,7 +1370,7 @@ int radeon_device_init(struct radeon_device *rdev,
 	if (rdev->family == CHIP_CEDAR)
 		dma_bits = 32;
 #endif
-
+	rdev->need_dma32 = dma_bits == 32;
 	r = dma_set_mask_and_coherent(&rdev->pdev->dev, DMA_BIT_MASK(dma_bits));
 	if (r) {
 		pr_warn("radeon: No suitable DMA available\n");
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index bdb4c0e0736ba2..3debaeb720d173 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -696,7 +696,7 @@ int radeon_ttm_init(struct radeon_device *rdev)
 			       rdev->ddev->anon_inode->i_mapping,
 			       rdev->ddev->vma_offset_manager,
 			       rdev->need_swiotlb,
-			       dma_addressing_limited(&rdev->pdev->dev));
+			       rdev->need_dma32);
 	if (r) {
 		DRM_ERROR("failed initializing buffer object driver(%d).\n", r);
 		return r;

base-commit: 20e03e7f6e8efd42168db6d3fe044b804e0ede8f
-- 
2.39.0.rc2