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Message-ID: <20241028105050.3559169-29-sashal@kernel.org>
Date: Mon, 28 Oct 2024 06:50:11 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Cc: Badal Nilawar <badal.nilawar@...el.com>,
Matthew Brost <matthew.brost@...el.com>,
Matthew Auld <matthew.auld@...el.com>,
John Harrison <John.C.Harrison@...el.com>,
Himal Prasad Ghimiray <himal.prasad.ghimiray@...el.com>,
Lucas De Marchi <lucas.demarchi@...el.com>,
Sasha Levin <sashal@...nel.org>,
thomas.hellstrom@...ux.intel.com,
rodrigo.vivi@...el.com,
maarten.lankhorst@...ux.intel.com,
mripard@...nel.org,
tzimmermann@...e.de,
airlied@...il.com,
simona@...ll.ch,
intel-xe@...ts.freedesktop.org,
dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.11 29/32] drm/xe/guc/ct: Flush g2h worker in case of g2h response timeout
From: Badal Nilawar <badal.nilawar@...el.com>
[ Upstream commit 22ef43c78647dd37b0dafe2182b8650b99dbbe59 ]
In case if g2h worker doesn't get opportunity to within specified
timeout delay then flush the g2h worker explicitly.
v2:
- Describe change in the comment and add TODO (Matt B/John H)
- Add xe_gt_warn on fence done after G2H flush (John H)
v3:
- Updated the comment with root cause
- Clean up xe_gt_warn message (John H)
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/issues/1620
Closes: https://gitlab.freedesktop.org/drm/xe/kernel/issues/2902
Signed-off-by: Badal Nilawar <badal.nilawar@...el.com>
Cc: Matthew Brost <matthew.brost@...el.com>
Cc: Matthew Auld <matthew.auld@...el.com>
Cc: John Harrison <John.C.Harrison@...el.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@...el.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@...el.com>
Acked-by: Matthew Brost <matthew.brost@...el.com>
Signed-off-by: Matthew Brost <matthew.brost@...el.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241017111410.2553784-2-badal.nilawar@intel.com
(cherry picked from commit e5152723380404acb8175e0777b1cea57f319a01)
Signed-off-by: Lucas De Marchi <lucas.demarchi@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/gpu/drm/xe/xe_guc_ct.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
index cd9918e3896c0..ab24053f8766f 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct.c
+++ b/drivers/gpu/drm/xe/xe_guc_ct.c
@@ -888,6 +888,24 @@ static int guc_ct_send_recv(struct xe_guc_ct *ct, const u32 *action, u32 len,
ret = wait_event_timeout(ct->g2h_fence_wq, g2h_fence.done, HZ);
+ /*
+ * Occasionally it is seen that the G2H worker starts running after a delay of more than
+ * a second even after being queued and activated by the Linux workqueue subsystem. This
+ * leads to G2H timeout error. The root cause of issue lies with scheduling latency of
+ * Lunarlake Hybrid CPU. Issue dissappears if we disable Lunarlake atom cores from BIOS
+ * and this is beyond xe kmd.
+ *
+ * TODO: Drop this change once workqueue scheduling delay issue is fixed on LNL Hybrid CPU.
+ */
+ if (!ret) {
+ flush_work(&ct->g2h_worker);
+ if (g2h_fence.done) {
+ xe_gt_warn(gt, "G2H fence %u, action %04x, done\n",
+ g2h_fence.seqno, action[0]);
+ ret = 1;
+ }
+ }
+
/*
* Ensure we serialize with completion side to prevent UAF with fence going out of scope on
* the stack, since we have no clue if it will fire after the timeout before we can erase
--
2.43.0
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