Re: [PATCH 1/2] serial: qcom-geni: fix opp vote on shutdown

Konrad Dybcio
2023-07-15T09:20:34Z

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