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From: Konrad Dybcio <konrad.dybcio@linaro.org>
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>
Subject: Re: [PATCH 1/2] serial: qcom-geni: fix opp vote on shutdown
Date: Sat, 15 Jul 2023 11:19:39 +0200	[thread overview]
Message-ID: <de6b5727-e15a-5d59-9b79-6ca7b01c8d63@linaro.org> (raw)
In-Reply-To: <ZLFk1Q0pTfYmB5EU@hovoldconsulting.com>

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

  reply	other threads:[~2023-07-15  9:20 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-14 13:02 [PATCH 0/2] serial: qcom-geni: fix opp vote on shutdown Johan Hovold
2023-07-14 13:02 ` [PATCH 1/2] " Johan Hovold
2023-07-14 14:29   ` Konrad Dybcio
2023-07-14 15:08     ` Johan Hovold
2023-07-15  9:19       ` Konrad Dybcio [this message]
2023-07-14 13:02 ` [PATCH 2/2] serial: qcom-geni: clean up clock-rate debug printk Johan Hovold
2023-07-14 14:26   ` Konrad Dybcio

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