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Message-ID: <de6b5727-e15a-5d59-9b79-6ca7b01c8d63@linaro.org>
Date:   Sat, 15 Jul 2023 11:19:39 +0200
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Subject: Re: [PATCH 1/2] serial: qcom-geni: fix opp vote on shutdown
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To:     Johan Hovold <johan@kernel.org>
Cc:     Johan Hovold <johan+linaro@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Rajendra Nayak <quic_rjendra@quicinc.com>,
        Matthias Kaehlcke <mka@chromium.org>
References: <20230714130214.14552-1-johan+linaro@kernel.org>
 <20230714130214.14552-2-johan+linaro@kernel.org>
 <e99b5975-b770-5460-1ce4-cd4eb1a50291@linaro.org>
 <ZLFk1Q0pTfYmB5EU@hovoldconsulting.com>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <ZLFk1Q0pTfYmB5EU@hovoldconsulting.com>
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On 14.07.2023 17:08, Johan Hovold wrote:
> On Fri, Jul 14, 2023 at 04:29:08PM +0200, Konrad Dybcio wrote:
>> On 14.07.2023 15:02, Johan Hovold wrote:
>>> The operating-performance-point vote needs to be dropped when shutting
>>> down the port to avoid wasting power by keeping resources like power
>>> domains in an unnecessarily high performance state (e.g. when a UART
>>> connected Bluetooth controller is not in use).
>>>
>>> Fixes: a5819b548af0 ("tty: serial: qcom_geni_serial: Use OPP API to set clk/perf state")
>>> Cc: stable@vger.kernel.org      # 5.9
>>> Cc: Rajendra Nayak <quic_rjendra@quicinc.com>
>>> Cc: Matthias Kaehlcke <mka@chromium.org>
>>> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
>>> ---
>> I don't know a whole lot about this subsystem, but the PM call has
>> a pointer to uport which already contains this clock rate.. Is it
>> zeroed out by the core before we reach it, which would prevent us
>> from reusing it?
> 
> No, but this driver has other issues and I couldn't be arsed fixing them
> before addressing this bug.
> 
> Specifically that uartclk variable can currently be set by userspace...
> 
> I'll fix that up next week.
OK sounds good

Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad
> 
> Johan