FAILED: patch "[PATCH] drm/i915/guc: clear stalled request after a reset" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

4595a2544344 ("drm/i915/guc: clear stalled request after a reset")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 4595a25443447b9542b2a5ee7961eb290e94b496 Mon Sep 17 00:00:00 2001
From: Daniele Ceraolo Spurio <[email protected]>
Date: Thu, 11 Aug 2022 14:08:12 -0700
Subject: [PATCH] drm/i915/guc: clear stalled request after a reset

If the GuC CTs are full and we need to stall the request submission while waiting for space, we save the stalled request and where the stall occurred; when the CTs have space again we pick up the request submission from where we left off.

If a full GT reset occurs, the state of all contexts is cleared and all non-guilty requests are unsubmitted, therefore we need to restart the stalled request submission from scratch. To make sure that we do so, clear the saved request after a reset.

Fixes note: the patch that introduced the bug is in 5.15, but no officially supported platform had GuC submission enabled by default in that kernel, so the backport to that particular version (and only that one) can potentially be skipped.

index 76916aed897a..834c707d1877 100644
@@ -4026,6 +4026,13 @@ static inline void guc_init_lrc_mapping(struct intel_guc *guc)
 	/* make sure all descriptors are clean... */
 	xa_destroy(&guc->context_lookup);
 
+	/*
+	 * A reset might have occurred while we had a pending stalled request,
+	 * so make sure we clean that up.
+	 */
+	guc->stalled_request = NULL;
+	guc->submission_stall_reason = STALL_NONE;
+
 	/*
 	 * Some contexts might have been pinned before we enabled GuC
 	 * submission, so we need to add them to the GuC bookeeping.