From f24044bd9b16a059e5773170fbfa1badc536d657 Mon Sep 17 00:00:00 2001 From: Darren Powell Date: Tue, 5 Apr 2022 22:17:08 -0400 Subject: [PATCH] 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 4ea5081c82c4 ("drm/amd/powerplay: enable SMC message filter") commit bf36b52e781d ("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 Reviewed-by: Luben Tuikov Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c index b8d0c70..f123198 100644 --- a/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c +++ b/drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c @@ -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. -- 2.7.4