[PATCH 1/3] drm/amdgpu: Fix hard hang for S/G display BOs.

[Andrey Grodzovsky]

HW requires for caching to be unset for scanout BO
mappings when the BO placement is in GTT memory.
Usually the flag to unset is passed from user mode
but for FB mode this was missing.

Suggested-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>
Tested-by: Shirish S <shirish.s at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c  | 14 +++++++++++---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c |  4 +++-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
index e476092..acc45125 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
@@ -137,14 +137,14 @@ static int amdgpufb_create_pinned_object(struct amdgpu_fbdev *rfbdev,
 	mode_cmd->pitches[0] = amdgpu_align_pitch(adev, mode_cmd->width, cpp,
 						  fb_tiled);
 	domain = amdgpu_display_supported_domains(adev);
-
 	height = ALIGN(mode_cmd->height, 8);
 	size = mode_cmd->pitches[0] * height;
 	aligned_size = ALIGN(size, PAGE_SIZE);
 	ret = amdgpu_gem_object_create(adev, aligned_size, 0, domain,
 				       AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED |
-				       AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS |
-				       AMDGPU_GEM_CREATE_VRAM_CLEARED,
+				       AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS     |
+				       AMDGPU_GEM_CREATE_VRAM_CLEARED 	     |
+				       AMDGPU_GEM_CREATE_CPU_GTT_USWC,
 				       ttm_bo_type_kernel, NULL, &gobj);
 	if (ret) {
 		pr_err("failed to allocate framebuffer (%d)\n", aligned_size);
@@ -166,6 +166,14 @@ static int amdgpufb_create_pinned_object(struct amdgpu_fbdev *rfbdev,
 			dev_err(adev->dev, "FB failed to set tiling flags\n");
 	}
 
+	/*
+	 * If the AMDGPU_GEM_CREATE_CPU_GTT_USWC flag was removed during BO
+	 * creation it means that USWC is not supported for this board and
+	 * so to avoid hang caused by placement of scanout BO in GTT on certain
+	 * APUs and still light up, force the BO placement to VRAM.
+	 */
+	if (abo->flags & ~AMDGPU_GEM_CREATE_CPU_GTT_USWC)
+		domain  = AMDGPU_GEM_DOMAIN_VRAM;
 
 	ret = amdgpu_bo_pin(abo, domain);
 	if (ret) {
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 2cead5a..b3b3b89 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -743,7 +743,8 @@ int amdgpu_mode_dumb_create(struct drm_file *file_priv,
 	struct amdgpu_device *adev = dev->dev_private;
 	struct drm_gem_object *gobj;
 	uint32_t handle;
-	u64 flags = AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
+	u64 flags = AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED |
+		    AMDGPU_GEM_CREATE_CPU_GTT_USWC;
 	u32 domain;
 	int r;
 
@@ -761,6 +762,7 @@ int amdgpu_mode_dumb_create(struct drm_file *file_priv,
 	args->size = ALIGN(args->size, PAGE_SIZE);
 	domain = amdgpu_bo_get_preferred_pin_domain(adev,
 				amdgpu_display_supported_domains(adev));
+
 	r = amdgpu_gem_object_create(adev, args->size, 0, domain, flags,
 				     ttm_bo_type_device, NULL, &gobj);
 	if (r)
-- 
2.7.4