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From: Matthew Auld <matthew.auld@intel.com>
To: intel-xe@lists.freedesktop.org
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Subject: [Intel-xe] [PATCH v9 6/8] drm/xe/ct: drop mem_access_get from g2h_worker_func()
Date: Tue, 23 May 2023 10:47:25 +0100	[thread overview]
Message-ID: <20230523094727.162266-6-matthew.auld@intel.com> (raw)
In-Reply-To: <20230523094727.162266-1-matthew.auld@intel.com>

In the next patch we track the current task executing the runtime_pm
callbacks, if any, in order to prevent the runtime_pm code waiting for
itself and deadlocking when called from the callbacks. However with
g2h_worker_func() we are processing g2h packets from a workqueue when
receiving an interrupt. The runtime callbacks needs to talk to the GuC
and so rely on this, however since these are processed from a workqueue
the current task will be different and when calling something like
mem_access_get() we deadlock. Callers should in theory already be
holding an access.ref when talking to the GuC (CT communication looks to
be disabled when suspending the GT).

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_guc_ct.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
index 7a8c9d6a03f3..6e0d2d06b7f5 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct.c
+++ b/drivers/gpu/drm/xe/xe_guc_ct.c
@@ -1081,7 +1081,6 @@ static void g2h_worker_func(struct work_struct *w)
 	struct xe_guc_ct *ct = container_of(w, struct xe_guc_ct, g2h_worker);
 	int ret;
 
-	xe_device_mem_access_get(ct_to_xe(ct));
 	do {
 		mutex_lock(&ct->lock);
 		ret = dequeue_one_g2h(ct);
@@ -1095,7 +1094,6 @@ static void g2h_worker_func(struct work_struct *w)
 			kick_reset(ct);
 		}
 	} while (ret == 1);
-	xe_device_mem_access_put(ct_to_xe(ct));
 }
 
 static void guc_ctb_snapshot_capture(struct xe_device *xe, struct guc_ctb *ctb,
-- 
2.40.1


  parent reply	other threads:[~2023-05-23  9:47 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-23  9:47 [Intel-xe] [PATCH v9 1/8] Revert "drm/xe: Use atomic instead of mutex for xe_device_mem_access_ongoing" Matthew Auld
2023-05-23  9:47 ` [Intel-xe] [PATCH v9 2/8] drm/xe: don't allocate under ct->lock Matthew Auld
2023-05-23  9:47 ` [Intel-xe] [PATCH v9 3/8] drm/xe: keep pulling mem_access_get further back Matthew Auld
2023-05-23  9:47 ` [Intel-xe] [PATCH v9 4/8] drm/xe: tweak lock ordering for freq_lock Matthew Auld
2023-05-23 13:07   ` Rodrigo Vivi
2023-05-23 13:13     ` Matthew Auld
2023-05-23  9:47 ` [Intel-xe] [PATCH v9 5/8] drm/xe/ggtt: prime ggtt->lock against FS_RECLAIM Matthew Auld
2023-05-23  9:47 ` Matthew Auld [this message]
2023-05-23 13:04   ` [Intel-xe] [PATCH v9 6/8] drm/xe/ct: drop mem_access_get from g2h_worker_func() Rodrigo Vivi
2023-05-23 13:10     ` Matthew Auld
2023-05-23  9:47 ` [Intel-xe] [PATCH v9 7/8] drm/xe: fix xe_device_mem_access_get() races Matthew Auld
2023-05-23  9:47 ` [Intel-xe] [PATCH v9 8/8] drm/xe: Use atomic for mem_access.ref Matthew Auld
2023-05-23  9:49 ` [Intel-xe] ✓ CI.Patch_applied: success for series starting with [v9,1/8] Revert "drm/xe: Use atomic instead of mutex for xe_device_mem_access_ongoing" Patchwork
2023-05-23  9:51 ` [Intel-xe] ✓ CI.KUnit: " Patchwork
2023-05-23  9:55 ` [Intel-xe] ✓ CI.Build: " Patchwork
2023-05-23 10:19 ` [Intel-xe] ○ CI.BAT: info " Patchwork

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