drm/xe: Add page queue multiplier

For an unknown reason the math to determine the PF queue size does is
not correct - compute UMD applications are overflowing the PF queue
which is fatal. A multippier of 8 fixes the problem.

Fixes: 3338e4f ("drm/xe: Use topology to determine page fault queue size")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Jagmeet Randhawa <jagmeet.randhawa@intel.com>
Link: https://lore.kernel.org/r/20250408155915.78770-1-matthew.brost@intel.com
(cherry picked from commit 29582e0)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>

Author: mbrost05

drivers/gpu/drm/xe/xe_gt_pagefault.c

@@ -435,9 +435,16 @@ static int xe_alloc_pf_queue(struct xe_gt *gt, struct pf_queue *pf_queue)
 	num_eus = bitmap_weight(gt->fuse_topo.eu_mask_per_dss,
 				XE_MAX_EU_FUSE_BITS) * num_dss;
 
-	/* user can issue separate page faults per EU and per CS */
+	/*
+	 * user can issue separate page faults per EU and per CS
+	 *
+	 * XXX: Multiplier required as compute UMD are getting PF queue errors
+	 * without it. Follow on why this multiplier is required.
+	 */
+#define PF_MULTIPLIER	8
 	pf_queue->num_dw =
-		(num_eus + XE_NUM_HW_ENGINES) * PF_MSG_LEN_DW;
+		(num_eus + XE_NUM_HW_ENGINES) * PF_MSG_LEN_DW * PF_MULTIPLIER;
+#undef PF_MULTIPLIER
 
 	pf_queue->gt = gt;
 	pf_queue->data = devm_kcalloc(xe->drm.dev, pf_queue->num_dw,