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* [PATCH] drm/xe: Store GMD_ID subunit during GT init
@ 2026-10-28  2:05 Pallavi Mishra
  2026-10-28  2:14 ` ✓ CI.KUnit: success for " Patchwork
                   ` (3 more replies)
  0 siblings, 4 replies; 7+ messages in thread
From: Pallavi Mishra @ 2026-10-28  2:05 UTC (permalink / raw)
  To: intel-xe, matthew.d.roper

Read GMD_ID during GT forcewake initialization and store both the
full GMD_ID value and the subip field in gt->info.
Keeping the field in gt->info provides a common source for
future users and avoids additional GMD_ID reads.

Signed-off-by: Pallavi Mishra <pallavi.mishra@intel.com>
---
 drivers/gpu/drm/xe/xe_gt.c       | 20 ++++++++++++++------
 drivers/gpu/drm/xe/xe_gt_types.h |  2 ++
 drivers/gpu/drm/xe/xe_guc.c      | 12 +++++-------
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index 60d35ada2853..39ae7105aaa0 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -564,6 +564,18 @@ static void dump_pat_on_error(struct xe_gt *gt)
 	xe_pat_dump(gt, &p);
 }
 
+/*
+ * Store GMD_ID and sub-IP before GuC upload. Main GAMCTRL consumes the stored
+ * subunit field during upload.
+ */
+static void xe_gt_read_gmdid(struct xe_gt *gt)
+{
+	u32 gmdid = xe_mmio_read32(&gt->mmio, GMD_ID);
+
+	gt->info.gmdid = gmdid;
+	gt->info.subip = REG_FIELD_GET(GMD_ID_SUBIP_FLAG_MASK, gmdid);
+}
+
 static int gt_init_with_gt_forcewake(struct xe_gt *gt)
 {
 	int err;
@@ -572,6 +584,8 @@ static int gt_init_with_gt_forcewake(struct xe_gt *gt)
 	if (!fw_ref.domains)
 		return -ETIMEDOUT;
 
+	xe_gt_read_gmdid(gt);
+
 	err = xe_uc_init(&gt->uc);
 	if (err)
 		return err;
@@ -610,12 +624,6 @@ static int gt_init_with_gt_forcewake(struct xe_gt *gt)
 	if (err)
 		return err;
 
-	/*
-	 * Stash hardware-reported version.  Since this register does not exist
-	 * on pre-MTL platforms, reading it there will (correctly) return 0.
-	 */
-	gt->info.gmdid = xe_mmio_read32(&gt->mmio, GMD_ID);
-
 	if (GRAPHICS_VER(gt_to_xe(gt)) >= 20 && xe_gt_is_main_type(gt))
 		gt->info.has_wmtp_disabled = !!(xe_mmio_read32(&gt->mmio, XEHP_FUSE4) &
 			CFEG_WMTP_DISABLE);
diff --git a/drivers/gpu/drm/xe/xe_gt_types.h b/drivers/gpu/drm/xe/xe_gt_types.h
index c00a7c171f80..c67fb0d512b0 100644
--- a/drivers/gpu/drm/xe/xe_gt_types.h
+++ b/drivers/gpu/drm/xe/xe_gt_types.h
@@ -153,6 +153,8 @@ struct xe_gt {
 		u64 engine_mask;
 		/** @info.gmdid: raw GMD_ID value from hardware */
 		u32 gmdid;
+		/** @info.subip: GMD_ID subunit field */
+		u8 subip;
 		/**
 		 * @info.multi_queue_engine_class_mask: Bitmask of engine classes with
 		 * multi queue support enabled.
diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
index b1f4e132fa0c..37d72ce1d589 100644
--- a/drivers/gpu/drm/xe/xe_guc.c
+++ b/drivers/gpu/drm/xe/xe_guc.c
@@ -1864,18 +1864,16 @@ bool xe_guc_using_main_gamctrl_queues(struct xe_guc *guc)
 	/*
 	 * For Xe3p media gt (35), the GuC and the CS subunits may be still Xe3
 	 * that lacks the Main GAMCTRL support. Reserved bits from the GMD_ID
-	 * inform the IP version of the subunits.
+	 * inform the IP version of the subunits. That field is captured once
+	 * at GT init and stored in gt->info.subip.
 	 */
 	if (xe_gt_is_media_type(gt) && MEDIA_VER(gt_to_xe(gt)) == 35) {
-		u32 val = xe_mmio_read32(&gt->mmio, GMD_ID);
-		u32 subip = REG_FIELD_GET(GMD_ID_SUBIP_FLAG_MASK, val);
-
-		if (!subip)
+		if (!gt->info.subip)
 			return true;
 
-		xe_gt_WARN(gt, subip != 1,
+		xe_gt_WARN(gt, gt->info.subip != 1,
 			   "GMD_ID has unknown value in the SUBIP_FLAG field - 0x%x\n",
-			   subip);
+			   gt->info.subip);
 
 		return false;
 	}
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2026-10-29 13:26 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-10-28  2:05 [PATCH] drm/xe: Store GMD_ID subunit during GT init Pallavi Mishra
2026-10-28  2:14 ` ✓ CI.KUnit: success for " Patchwork
2026-10-28  2:48 ` ✓ Xe.CI.BAT: " Patchwork
2026-10-28  7:19 ` ✓ Xe.CI.FULL: " Patchwork
2026-10-28 18:53 ` [PATCH] " Gustavo Sousa
2026-10-29  0:37   ` Mishra, Pallavi
2026-10-29 13:26     ` Gustavo Sousa

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