drm/xe: Add multi_queue_active_lrca debugfs

Add a per-GT debugfs file, multi_queue_active_lrca, that prints, for
every engine supporting multi-queue, the currently active queue ID
(CSMQDEBUG) and the LRCA of the exec queue occupying that slot within
the running multi-queue group.

RING_CURRENT_LRCA only reports the primary queue's LRCA for the group
and does not update to reflect the active queue in multi-queue mode,
which makes it hard to tell which queue is actually running when
debugging multi-queue CSB/context-switch issues. Resolve the active
LRCA by matching the primary LRCA against each queue's group and
picking the queue at the reported active_id position.

v4:
 - Extracted multi_queue_active_lrca into a dedicated
   multi_queue_debugfs_list to prevent debugfs node registration on
   platforms lacking multi-queue support entirely, via
   xe_gt_has_multi_queue() gating. (Tejas)
v3:
 - Use xe_exec_queue_get_lrc() instead of raw pointer dereference to
   safely handle concurrent multi-queue group creation and avoid race
   conditions (Sashiko)
v2:
 - Maintain alphabetical order for includes and
   pf_only_debugfs_list (Tejas)
 - Export and reuse xe_lrc_get_multi_queue_active_queue_id() instead
   of duplicate MMIO read (Tejas)

Bspec: 60321, 73976
Signed-off-by: Varun Gupta <varun.gupta@intel.com>
Link: https://patch.msgid.link/20260908033417.1019602-2-varun.gupta@intel.com
Reviewed-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>

0 files changed, 0 insertions, 0 deletions