Messages in this thread | | | Subject | Re: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up | From | Suzuki Poulose <> | Date | Fri, 16 Oct 2020 12:21:15 +0100 |
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Hi Sai,
On 10/16/20 11:10 AM, Sai Prakash Ranjan wrote: > There is a bug on the systems supporting to skip power up > (qcom,skip-power-up) where setting LPOVERRIDE bit(low-power > state override behaviour) will result in CPU hangs/lockups > even on the implementations which supports it. So skip > setting the LPOVERRIDE bit for such platforms. > > Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up") > Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
The fix is fine by me. Btw, is there a hardware Erratum assigned for this ? It would be good to have the Erratum documented somewhere, preferrably ( Documentation/arm64/silicon-errata.rst )
> --- > drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c > index abd706b216ac..6096d7abf80d 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -779,7 +779,7 @@ static void etm4_init_arch_data(void *info) > * LPOVERRIDE, bit[23] implementation supports > * low-power state override > */ > - if (BMVAL(etmidr5, 23, 23)) > + if (BMVAL(etmidr5, 23, 23) && (!drvdata->skip_power_up)) > drvdata->lpoverride = true; > else > drvdata->lpoverride = false; > > base-commit: 3477326277451000bc667dfcc4fd0774c039184c >
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