drm/xe: Always check force_wake_get return code

A force_wake_get failure means that the HW might not be awake for the
access we're doing; this can lead to an immediate error or it can be a
more subtle problem (e.g. a register read might return an incorrect
value that is still valid, leading the driver to make a wrong choice
instead of flagging an error).
We avoid an error from the force_wake function because callers might
handle or tolerate the error, but this only works if all callers
are checking the error code. The majority already do, but a few are not.
These are mainly falling into 3 categories, which are each handled
differently:

1) error capture: in this case we want to continue the capture, but we
   log an info message in dmesg to notify the user that the capture
   might have incorrect data.

2) ioctl: in this case we return a -EIO error to userspace

3) unabortable actions: these are scenarios where we can't simply abort
   and retry and so it's better to just try it anyway because there is a
   chance the HW is awake even with the failure. In this case we throw a
   warning so we know there was a forcewake problem if something fails
   down the line.

v2: use gt_WARN_ON where appropriate

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tejas Upadhyay <tejas.upadhyay@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240318154924.3453513-1-daniele.ceraolospurio@intel.com

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
index 4a2b8e6b81b8..a71be57f0fc2 100644
--- a/drivers/gpu/drm/xe/xe_guc_submit.c
+++ b/drivers/gpu/drm/xe/xe_guc_submit.c
@@ -833,7 +833,9 @@ static void simple_error_capture(struct xe_exec_queue *q)
 			}
 		}
 
-		xe_force_wake_get(gt_to_fw(guc_to_gt(guc)), XE_FORCEWAKE_ALL);
+		if (xe_force_wake_get(gt_to_fw(guc_to_gt(guc)), XE_FORCEWAKE_ALL))
+			xe_gt_info(guc_to_gt(guc),
+				   "failed to get forcewake for error capture");
 		xe_guc_ct_print(&guc->ct, &p, true);
 		guc_exec_queue_print(q, &p);
 		for_each_hw_engine(hwe, guc_to_gt(guc), id) {