drm/xe: Disable timestamp WA on VFs

The timestamp WA does not work on a VF because it requires reading MMIO
registers, which are inaccessible on a VF. This timestamp WA confuses
LRC sampling on a VF during TDR, as the LRC timestamp would always read
as 1 for any active context. Disable the timestamp WA on VFs to avoid
this confusion.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Fixes: 617d824c5323 ("drm/xe: Add WA BB to capture active context utilization")
Link: https://patch.msgid.link/20260110012739.2888434-7-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
index 70eae7d03a2724058e8382e12b22c0c0ecdf2025..bf27fc9eebd37136ca454ae984f1d0258218ed48 100644 (file)
--- a/drivers/gpu/drm/xe/xe_lrc.c
+++ b/drivers/gpu/drm/xe/xe_lrc.c
@@ -1068,6 +1068,9 @@ static ssize_t setup_utilization_wa(struct xe_lrc *lrc,
 {
        u32 *cmd = batch;
 
+       if (IS_SRIOV_VF(gt_to_xe(lrc->gt)))
+               return 0;
+
        if (xe_gt_WARN_ON(lrc->gt, max_len < 12))
                return -ENOSPC;