linux-kernel - Re: [PATCH V2 1/2] soc: qcom-geni-se: Cleanup the code to remove proxy votes

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Date:   Mon, 22 Mar 2021 16:32:27 +0530
From:   rojay@...eaurora.org
To:     Matthias Kaehlcke <mka@...omium.org>
Cc:     agross@...nel.org, bjorn.andersson@...aro.org,
        gregkh@...uxfoundation.org, robh+dt@...nel.org,
        linux-serial@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Rajendra Nayak <rnayak@...eaurora.org>,
        akashast@...eaurora.org, msavaliy@....qualcomm.com
Subject: Re: [PATCH V2 1/2] soc: qcom-geni-se: Cleanup the code to remove
 proxy votes

On 2021-03-18 22:43, Matthias Kaehlcke wrote:
> On Thu, Mar 18, 2021 at 04:40:08PM +0530, Roja Rani Yarubandi wrote:
>> ICC core and platforms drivers supports sync_state feature, which
>> ensures that the default ICC BW votes from the bootloader is not
>> removed until all it's consumers are probes.
>> 
>> The proxy votes were needed in case other QUP child drivers
>> I2C, SPI probes before UART, they can turn off the QUP-CORE clock
>> which is shared resources for all QUP driver, this causes unclocked
>> access to HW from earlycon.
>> 
>> Given above support from ICC there is no longer need to maintain
>> proxy votes on QUP-CORE ICC node from QUP wrapper driver for early
>> console usecase, the default votes won't be removed until real
>> console is probed.
>> 
>> Signed-off-by: Roja Rani Yarubandi <rojay@...eaurora.org>
>> Signed-off-by: Akash Asthana <akashast@...eaurora.org>
> 
> I suggest to mention that this is essentially a revert of commit
> 048eb908a1f2 ("soc: qcom-geni-se: Add interconnect support to fix
> earlycon crash"). This makes the life of reviewers easier and it's
> also good to have the reference in the git history.
> 

Ok.

> You could also mention commit 7d3b0b0d8184 ("interconnect: qcom:
> Use icc_sync_state") in the intro.
> 

Ok.

> I tried to test by first reproducing the original issue without
> 'sync_state' in the ICC, but wasn't successful, probably something
> changed in the boot/ICC timing in the meantime ¯\_(ツ)_/¯.
> 

Need to remove runtime auto suspend support from SPI/I2C as well, as it 
was
masking the issue by delaying to turn off the resources by 250ms.

> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>