[PATCH] drm/amd/amdgpu: Disable GFX_PG on laptop raven part

[StDenis, Tom]

GFX_PG causes visual (and likely memory) corruption on laptop
raven parts.  Until it's fully diagnosed let's disable it to ensure
stable operation.

Tested on a Dell Latitude 5495.

Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/soc15.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/soc15.c b/drivers/gpu/drm/amd/amdgpu/soc15.c
index 77e679920c1c..27a500f75f57 100644
--- a/drivers/gpu/drm/amd/amdgpu/soc15.c
+++ b/drivers/gpu/drm/amd/amdgpu/soc15.c
@@ -1138,6 +1138,11 @@ static int soc15_common_early_init(void *handle)
 			adev->pg_flags |= AMD_PG_SUPPORT_GFX_PG |
 				AMD_PG_SUPPORT_CP |
 				AMD_PG_SUPPORT_RLC_SMU_HS;
+
+		// disable GFX_PG until debugged.
+		if (adev->external_rev_id == 0x21)
+			adev->pg_flags &= ~AMD_PG_SUPPORT_GFX_PG;
+
 		break;
 	case CHIP_ARCTURUS:
 		adev->asic_funcs = &vega20_asic_funcs;
-- 
2.21.0