drm/amdgpu: update comments about s0ix suspend/resume

Provide and explanation as to why we skip GFX and PSP for
S0ix.  GFX goes into gfxoff, same as runtime, so no need
to tear down and re-init.  PSP is part of the always on
state, so no need to touch it.

Acked-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
index 5ec9b87..5796331 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
@@ -2754,10 +2754,14 @@ static int amdgpu_device_ip_suspend_phase2(struct amdgpu_device *adev)
                        continue;
                }
 
-               /* XXX fix these remaining cases */
+               /* skip suspend of gfx and psp for S0ix
+                * gfx is in gfxoff state, so on resume it will exit gfxoff just
+                * like at runtime. PSP is also part of the always on hardware
+                * so no need to suspend it.
+                */
                if (adev->in_s0ix &&
-                   (adev->ip_blocks[i].version->type == AMD_IP_BLOCK_TYPE_PSP || /* breaks resume */
-                    adev->ip_blocks[i].version->type == AMD_IP_BLOCK_TYPE_GFX))  /* breaks suspend */
+                   (adev->ip_blocks[i].version->type == AMD_IP_BLOCK_TYPE_PSP ||
+                    adev->ip_blocks[i].version->type == AMD_IP_BLOCK_TYPE_GFX))
                        continue;
 
                /* XXX handle errors */