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Subject: Re: [PATCHv8 2/5] arm64: dts: qcom: msm8998: Add Coresight support
To:     Suzuki K Poulose <suzuki.poulose@arm.com>,
        gregkh@linuxfoundation.org, mathieu.poirier@linaro.org,
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        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
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References: <cover.1562940244.git.saiprakash.ranjan@codeaurora.org>
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 <3b192063-f31f-b861-d913-61d737cecc57@arm.com>
From:   Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Message-ID: <4854b0f7-6a81-bc87-3e63-d2b7c68a44f6@codeaurora.org>
Date:   Thu, 18 Jul 2019 14:44:01 +0530
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Hi Suzuki,

On 7/18/2019 1:58 PM, Suzuki K Poulose wrote:
> Hi Sai,
> 
> 
>          etr@6048000 {
>> +            compatible = "arm,coresight-tmc", "arm,primecell";
>> +            reg = <0x06048000 0x1000>;
>> +
>> +            clocks = <&rpmcc RPM_SMD_QDSS_CLK>, <&rpmcc 
>> RPM_SMD_QDSS_A_CLK>;
>> +            clock-names = "apb_pclk", "atclk";
>> +            arm,scatter-gather;
> 
> Please could you confirm that you have tested the scatter-gather mode 
> with ETR ? Either via perf/sysfs. Please could you share your results ? 
> Unless verified
> this is going to be fatal for the system.
> 
> Similarly for other platforms.
> 

Yes I have tested with scatter-gather mode with ETR on all platforms
which I have posted via sysfs(not perf) before on previous versions of 
this patch series and no issues were found. And I suppose this was
discussed in v2 of this patch series [1].

As said in one of the series initially [1], QCOM msm downstream kernels 
have been using scatter gather mode and we haven't seen any fatal issues.

[1] https://patchwork.kernel.org/patch/10769535/

Thanks,
Sai

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