This is a note to let you know that I've just added the patch titled
perf: imx_perf: fix counter start and config sequence
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-imx_perf-fix-counter-start-and-config-sequence.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a0bf93f28f3a01e537cf93d8ea70115c84ab3467
Author: Xu Yang <xu.yang_2@xxxxxxx>
Date: Wed May 29 16:03:55 2024 +0800
perf: imx_perf: fix counter start and config sequence
[ Upstream commit ac9aa295f7a89d38656739628796f086f0b160e2 ]
In current driver, the counter will start firstly and then be configured.
This sequence is not correct for AXI filter events since the correct
AXI_MASK and AXI_ID are not set yet. Then the results may be inaccurate.
Reviewed-by: Frank Li <Frank.Li@xxxxxxx>
Fixes: 55691f99d417 ("drivers/perf: imx_ddr: Add support for NXP i.MX9 SoC DDRC PMU driver")
cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
Link: https://lore.kernel.org/r/20240529080358.703784-5-xu.yang_2@xxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/perf/fsl_imx9_ddr_perf.c b/drivers/perf/fsl_imx9_ddr_perf.c
index 5cf770a1bc312..4f6eade522024 100644
--- a/drivers/perf/fsl_imx9_ddr_perf.c
+++ b/drivers/perf/fsl_imx9_ddr_perf.c
@@ -476,12 +476,12 @@ static int ddr_perf_event_add(struct perf_event *event, int flags)
hwc->idx = counter;
hwc->state |= PERF_HES_STOPPED;
- if (flags & PERF_EF_START)
- ddr_perf_event_start(event, flags);
-
/* read trans, write trans, read beat */
ddr_perf_monitor_config(pmu, cfg, cfg1, cfg2);
+ if (flags & PERF_EF_START)
+ ddr_perf_event_start(event, flags);
+
return 0;
}
