From: Bhaumik Vasav Bhatt <quic_bbhatt@quicinc.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
<mhi@lists.linux.dev>
Cc: <quic_hemantk@quicinc.com>, <linux-arm-msm@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <loic.poulain@linaro.org>,
<stable@vger.kernel.org>
Subject: Re: [PATCH v2] bus: mhi: host: pci_generic: Add missing poweroff() PM callback
Date: Tue, 5 Apr 2022 13:23:22 -0700 [thread overview]
Message-ID: <daafdfd8-312e-cf42-d7bb-3fb914d443dc@quicinc.com> (raw)
In-Reply-To: <20220405125907.5644-1-manivannan.sadhasivam@linaro.org>
On 4/5/2022 5:59 AM, Manivannan Sadhasivam wrote:
> During hibernation process, once thaw() stage completes, the MHI endpoint
> devices will be in M0 state post recovery. After that, the devices will be
> powered down so that the system can enter the target sleep state. During
> this stage, the PCI core will put the devices in D3hot. But this transition
> is allowed by the MHI spec. The devices can only enter D3hot when it is in
> M3 state.
>
> So for fixing this issue, let's add the poweroff() callback that will get
> executed before putting the system in target sleep state during
> hibernation. This callback will power down the device properly so that it
> could be restored during restore() or thaw() stage.
>
> Cc: stable@vger.kernel.org
> Fixes: 5f0c2ee1fe8d ("bus: mhi: pci-generic: Fix hibernation")
> Reported-by: Hemant Kumar <quic_hemantk@quicinc.com>
> Suggested-by: Hemant Kumar <quic_hemantk@quicinc.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>
> Changes in v2:
>
> * Hemant suggested to use restore function for poweroff() callback as we can
> make sure that the device gets powered down properly.
>
> drivers/bus/mhi/host/pci_generic.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/bus/mhi/host/pci_generic.c b/drivers/bus/mhi/host/pci_generic.c
> index 9527b7d63840..ef85dbfb3216 100644
> --- a/drivers/bus/mhi/host/pci_generic.c
> +++ b/drivers/bus/mhi/host/pci_generic.c
> @@ -1085,6 +1085,7 @@ static const struct dev_pm_ops mhi_pci_pm_ops = {
> .resume = mhi_pci_resume,
> .freeze = mhi_pci_freeze,
> .thaw = mhi_pci_restore,
> + .poweroff = mhi_pci_freeze,
It is possible that .thaw() queues recovery work and recovery work is
still running
while .poweroff() is called. I would suggest adding a flush_work() in
freeze such that
we don't try to power off while we're also trying to power on MHI from
recovery work.
> .restore = mhi_pci_restore,
> #endif
> };
next prev parent reply other threads:[~2022-04-05 21:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 12:59 [PATCH v2] bus: mhi: host: pci_generic: Add missing poweroff() PM callback Manivannan Sadhasivam
2022-04-05 20:23 ` Bhaumik Vasav Bhatt [this message]
2022-04-07 14:00 ` Manivannan Sadhasivam
2022-04-11 6:07 ` Manivannan Sadhasivam
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