Commit f24044bd authored Apr 05, 2022 by Darren Powell Committed by Alex Deucher Apr 19, 2022

amdgpu/pm: Clarify documentation of error handling in send_smc_mesg



Clarify the smu_cmn_send_smc_msg_with_param documentation to mention two
cases exist where messages are silently dropped with no error returned.
These cases occur in unusual situations where either:
 1. the message type is not allowed to a virtual GPU, or
 2. a PCI recovery is underway and the HW is not yet in sync with the SW

For more details see
 commit 4ea5081c ("drm/amd/powerplay: enable SMC message filter")
 commit bf36b52e ("drm/amdgpu: Avoid accessing HW when suspending SW state")

(v2)
  Reworked with suggestions from Luben & Paul

(v3)
  Updated wording as per Luben's feedback
  Corrected error stating all messages denied on virtual GPU
  (each GPU has mask of which messages are allowed)

Signed-off-by: Darren Powell <darren.powell@amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

parent eea5c7b3

drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -356,9 +356,11 @@ int smu_cmn_wait_for_response(struct smu_context *smu)
		* completion of the command, and return back a value from the SMU in
		* @read_arg pointer.
		*
		* Return 0 on success, -errno on error, if we weren't able to send
		* the message or if the message completed with some kind of
		* error. See __smu_cmn_reg2errno() for details of the -errno.
		* Return 0 on success, -errno when a problem is encountered sending
		* message or receiving reply. If there is a PCI bus recovery or
		* the destination is a virtual GPU which does not allow this message
		* type, the message is simply dropped and success is also returned.
		* See __smu_cmn_reg2errno() for details of the -errno.
		*
		* If we weren't able to send the message to the SMU, we also print
		* the error to the standard log.