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Date:   Mon, 31 May 2021 10:54:16 +0530
From:   rojay@codeaurora.org
To:     Roja Rani Yarubandi <rojay@codeaurora.org>
Cc:     swboyd@chromium.org, dianders@chromium.org,
        saiprakash.ranjan@codeaurora.org, gregkh@linuxfoundation.org,
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        sumit.semwal@linaro.org, linux-media@vger.kernel.org
Subject: Re: [PATCH V11 1/2] i2c: i2c-qcom-geni: Add shutdown callback for i2c
In-Reply-To: <YLClq6hZKUA1Y4ZW@kunai>
References: <20210525131051.31250-1-rojay@codeaurora.org>
 <20210525131051.31250-2-rojay@codeaurora.org> <YLClq6hZKUA1Y4ZW@kunai>
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On 2021-05-28 13:41, Wolfram Sang wrote:
> On Tue, May 25, 2021 at 06:40:50PM +0530, Roja Rani Yarubandi wrote:
>> If the hardware is still accessing memory after SMMU translation
>> is disabled (as part of smmu shutdown callback), then the
>> IOVAs (I/O virtual address) which it was using will go on the bus
>> as the physical addresses which will result in unknown crashes
>> like NoC/interconnect errors.
>> 
>> So, implement shutdown callback for i2c driver to suspend the bus
>> during system "reboot" or "shutdown".
>> 
>> Fixes: 37692de5d523 ("i2c: i2c-qcom-geni: Add bus driver for the 
>> Qualcomm GENI I2C controller")
>> Signed-off-by: Roja Rani Yarubandi <rojay@codeaurora.org>
> 
> Do we need patch 1 after patch 2 was applied? I always thought all
> devices are suspended before shutdown/reboot?
> 

Yes, both patch 1 and patch 2 are required.
Devices are not suspended during shutdown/reboot.

> Nice to see that 'mark_adapter_suspended' becomes useful again!

Thanks,
Roja