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Message-ID: <4490d181-7bf2-791c-1778-1102e9adbc25@quicinc.com>
Date:   Thu, 15 Sep 2022 12:55:58 +0530
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Subject: Re: [PATCH 3/3] clk: qcom: gcc-sc7280: Update the .pwrsts for usb
 gdsc
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To:     Matthias Kaehlcke <mka@chromium.org>,
        Johan Hovold <johan@kernel.org>
CC:     <andersson@kernel.org>, <agross@kernel.org>,
        <konrad.dybcio@somainline.org>, <mturquette@baylibre.com>,
        <sboyd@kernel.org>, <johan+linaro@kernel.org>,
        <quic_kriskura@quicinc.com>, <dianders@chromium.org>,
        <linux-clk@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20220901101756.28164-1-quic_rjendra@quicinc.com>
 <20220901101756.28164-3-quic_rjendra@quicinc.com>
 <YxDYJ+ONryLROBhL@google.com> <YyF+5CQqcLQlXvzV@hovoldconsulting.com>
 <YyJGNR33JbHxWWYD@google.com>
From:   Rajendra Nayak <quic_rjendra@quicinc.com>
In-Reply-To: <YyJGNR33JbHxWWYD@google.com>
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On 9/15/2022 2:53 AM, Matthias Kaehlcke wrote:
> On Wed, Sep 14, 2022 at 09:12:36AM +0200, Johan Hovold wrote:
>> On Thu, Sep 01, 2022 at 09:04:55AM -0700, Matthias Kaehlcke wrote:
>>> On Thu, Sep 01, 2022 at 03:47:56PM +0530, Rajendra Nayak wrote:
>>>> USB on sc7280 cannot support wakeups from low power states
>>>> if the GDSC is turned OFF. Update the .pwrsts for usb GDSC so it
>>>> only transitions to RET in low power.
>>>>
>>>> Signed-off-by: Rajendra Nayak <quic_rjendra@quicinc.com>
>>>
>>> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
>>> Tested-by: Matthias Kaehlcke <mka@chromium.org>
>>
>> Did you confirm that you actually hit the retention state?
> 
> No, how would I do that?
> 
>> IIUC, this series is equivalent to using ALWAYS_ON unless CX is actually
>> powered off during suspend.
> 
> The count in /sys/kernel/debug/qcom_stats/cxsd increses with each suspend,
> however it also does that with the GDSC configured as ALWAYS_ON and with
> Rajendra's "arm64: dts: qcom: sc7280: Add required-opps for USB" [1], so

hmm, that's really not expected. With my above patch and with the GDSC as
ALWAYS_ON there is a cx vote in suspend preventing cxsd so the counter
should not go up.

> I guess that isn't the correct signal.
> 
> https://patchwork.kernel.org/project/linux-arm-msm/patch/20220914053017.23617-1-quic_rjendra@quicinc.com/