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Date:   Fri, 16 Oct 2020 10:31:01 -0600
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc:     Suzuki K Poulose <suzuki.poulose@arm.com>,
        Mike Leach <mike.leach@linaro.org>, coresight@lists.linaro.org,
        Stephen Boyd <swboyd@chromium.org>, denik@chromium.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for
 qcom,skip-power-up
Message-ID: <20201016163101.GA3885@xps15>
References: <20201016101025.26505-1-saiprakash.ranjan@codeaurora.org>
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In-Reply-To: <20201016101025.26505-1-saiprakash.ranjan@codeaurora.org>
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On Fri, Oct 16, 2020 at 03:40:25PM +0530, 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>
> ---
>  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;
>

I have applied your patch.

Thanks,
Mathieu
 
> base-commit: 3477326277451000bc667dfcc4fd0774c039184c
> -- 
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