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, 7 insertions, 2 deletions

diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
index 0fcd30680323..7d3aa6bd3524 100644
--- a/drivers/gpu/drm/xe/xe_devcoredump.c
+++ b/drivers/gpu/drm/xe/xe_devcoredump.c
@@ -13,6 +13,7 @@
 #include "xe_exec_queue.h"
 #include "xe_force_wake.h"
 #include "xe_gt.h"
+#include "xe_gt_printk.h"
 #include "xe_guc_ct.h"
 #include "xe_guc_submit.h"
 #include "xe_hw_engine.h"
@@ -64,7 +65,9 @@ static void xe_devcoredump_deferred_snap_work(struct work_struct *work)
 {
 	struct xe_devcoredump_snapshot *ss = container_of(work, typeof(*ss), work);
 
-	xe_force_wake_get(gt_to_fw(ss->gt), XE_FORCEWAKE_ALL);
+	/* keep going if fw fails as we still want to save the memory and SW data */
+	if (xe_force_wake_get(gt_to_fw(ss->gt), XE_FORCEWAKE_ALL))
+		xe_gt_info(ss->gt, "failed to get forcewake for coredump capture\n");
 	xe_vm_snapshot_capture_delayed(ss->vm);
 	xe_guc_exec_queue_snapshot_capture_delayed(ss->ge);
 	xe_force_wake_put(gt_to_fw(ss->gt), XE_FORCEWAKE_ALL);
@@ -180,7 +183,9 @@ static void devcoredump_snapshot(struct xe_devcoredump *coredump,
 		}
 	}
 
-	xe_force_wake_get(gt_to_fw(q->gt), XE_FORCEWAKE_ALL);
+	/* keep going if fw fails as we still want to save the memory and SW data */
+	if (xe_force_wake_get(gt_to_fw(q->gt), XE_FORCEWAKE_ALL))
+		xe_gt_info(ss->gt, "failed to get forcewake for coredump capture\n");
 
 	coredump->snapshot.ct = xe_guc_ct_snapshot_capture(&guc->ct, true);
 	coredump->snapshot.ge = xe_guc_exec_queue_snapshot_capture(job);