[PATCH v2 1/2] drm/amd/display: fix the white screen issue when >= 64GB DRAM

[Hamza Mahfooz]

From: Yifan Zhang <yifan1.zhang at amd.com>

Dropping bit 31:4 of page table base is wrong, it makes page table
base points to wrong address if phys addr is beyond 64GB; dropping
page_table_start/end bit 31:4 is unnecessary since dcn20_vmid_setup
will do that. Also, while we are at it, cleanup the assignments using
upper_32_bits()/lower_32_bits() and AMDGPU_GPU_PAGE_SHIFT.

Cc: stable at vger.kernel.org
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2354
Fixes: 81d0bcf99009 ("drm/amdgpu: make display pinning more flexible (v2)")
Signed-off-by: Yifan Zhang <yifan1.zhang at amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz at amd.com>
---
v2: use upper_32_bits()/lower_32_bits() and AMDGPU_GPU_PAGE_SHIFT
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 1bb1a394f55f..5f14cd9391ca 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1283,11 +1283,15 @@ static void mmhub_read_system_context(struct amdgpu_device *adev, struct dc_phy_
 
 	pt_base = amdgpu_gmc_pd_addr(adev->gart.bo);
 
-	page_table_start.high_part = (u32)(adev->gmc.gart_start >> 44) & 0xF;
-	page_table_start.low_part = (u32)(adev->gmc.gart_start >> 12);
-	page_table_end.high_part = (u32)(adev->gmc.gart_end >> 44) & 0xF;
-	page_table_end.low_part = (u32)(adev->gmc.gart_end >> 12);
-	page_table_base.high_part = upper_32_bits(pt_base) & 0xF;
+	page_table_start.high_part = upper_32_bits(adev->gmc.gart_start >>
+						   AMDGPU_GPU_PAGE_SHIFT);
+	page_table_start.low_part = lower_32_bits(adev->gmc.gart_start >>
+						  AMDGPU_GPU_PAGE_SHIFT);
+	page_table_end.high_part = upper_32_bits(adev->gmc.gart_end >>
+						 AMDGPU_GPU_PAGE_SHIFT);
+	page_table_end.low_part = lower_32_bits(adev->gmc.gart_end >>
+						AMDGPU_GPU_PAGE_SHIFT);
+	page_table_base.high_part = upper_32_bits(pt_base);
 	page_table_base.low_part = lower_32_bits(pt_base);
 
 	pa_config->system_aperture.start_addr = (uint64_t)logical_addr_low << 18;
-- 
2.41.0