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Subject: Re: [RFC 4/8] clk: qcom: gcc-sm8450: Keep usb30 prim gdsc on during runtime suspend
From:   Stephen Boyd <sboyd@kernel.org>
Cc:     linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, quic_ppratap@quicinc.com,
        quic_jackp@quicinc.com,
        Krishna Kurapati <quic_kriskura@quicinc.com>
To:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Krishna Kurapati <quic_kriskura@quicinc.com>,
        Michael Turquette <mturquette@baylibre.com>
Date:   Wed, 18 Oct 2023 17:58:38 -0700
User-Agent: alot/0.10
Precedence: bulk

Quoting Krishna Kurapati (2023-10-17 06:19:44)
> When runtime suspend happens in host mode, if cable is removed at this
> instant, it triggers a resume where a xhci register access is done when
> gdsc is not on leading to a crash. Keep usb30 prim gdsc as on during
> runtime suspend to avoid this crash.
>=20
> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> ---
> Note: I am not sure if this is the right way or setting GDSC flags to
> PWRSTS_RET_ON is the right approach. So for now made this change to

Does using PWRSTS_RET_ON work? Does the GDSC support being turned off or
is the lowest power state retention?