* FAILED: patch "[PATCH] drm/i915/gt: Flush xcs before tgl breadcrumbs" failed to apply to 5.9-stable tree
@ 2020-11-09 10:48 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2020-11-09 10:48 UTC (permalink / raw)
To: chris, mika.kuoppala, rodrigo.vivi; +Cc: stable
The patch below does not apply to the 5.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e67d01d8494640018b08cd767aeb2824a8e11983 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 2 Nov 2020 22:10:57 +0000
Subject: [PATCH] drm/i915/gt: Flush xcs before tgl breadcrumbs
In a simple test case that writes to scratch and then busy-waits for the
batch to be signaled, we observe that the signal is before the write is
posted. That is bad news.
Splitting the flush + write_dword into two separate flush_dw prevents
the issue from being reproduced, we can presume the post-sync op is not
so post-sync.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/216
Testcase: igt/gem_exec_fence/parallel
Testcase: igt/i915_selftest/live/gt_timelines
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: stable@vger.kernel.org
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201102221057.29626-2-chris@chris-wilson.co.uk
(cherry picked from commit 09212e81e5450743e5b06b27c4e344e4c45b630d)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index d12861cf0753..f82c6dd1de18 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -4994,7 +4994,9 @@ gen12_emit_fini_breadcrumb_tail(struct i915_request *request, u32 *cs)
static u32 *gen12_emit_fini_breadcrumb(struct i915_request *rq, u32 *cs)
{
- return gen12_emit_fini_breadcrumb_tail(rq, emit_xcs_breadcrumb(rq, cs));
+ /* XXX Stalling flush before seqno write; post-sync not */
+ cs = emit_xcs_breadcrumb(rq, __gen8_emit_flush_dw(cs, 0, 0, 0));
+ return gen12_emit_fini_breadcrumb_tail(rq, cs);
}
static u32 *
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2020-11-09 10:48 FAILED: patch "[PATCH] drm/i915/gt: Flush xcs before tgl breadcrumbs" failed to apply to 5.9-stable tree gregkh
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