drm/amdgpu: check scratch registers to see if we need post (v2)

Rather than checking the CONGIG_MEMSIZE register as that may
not be reliable on some APUs.

v2: The scratch register is only used on CIK+

Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 541695768f0a..d92ac5c1af54 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -736,7 +736,12 @@ bool amdgpu_need_post(struct amdgpu_device *adev)
                 adev->has_hw_reset = false;
                 return true;
         }
-        /* then check MEM_SIZE, in case the crtcs are off */
+
+        /* bios scratch used on CIK+ */
+        if (adev->asic_type >= CHIP_BONAIRE)
+                return amdgpu_atombios_scratch_need_asic_init(adev);
+
+        /* check MEM_SIZE for older asics */
         reg = amdgpu_asic_get_config_memsize(adev);
 
         if ((reg != 0) && (reg != 0xffffffff))