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Subject: Re: Regarding usb dwc3 core shutdown callback
To:     Felipe Balbi <balbi@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        linux-arm-msm@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Pratham Pratap <prathampratap@codeaurora.org>,
        Jack Pham <jackp@codeaurora.org>,
        Stephen Boyd <swboyd@chromium.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        Doug Anderson <dianders@chromium.org>
References: <e34c8e16-6521-c6e4-f3ed-9d8520d4ece2@codeaurora.org>
 <87bl63yqq8.fsf@kernel.org>
From:   Sandeep Maheswaram <sanm@codeaurora.org>
Message-ID: <eb975a76-1482-f502-4dc1-7993cc3f30d0@codeaurora.org>
Date:   Thu, 26 Aug 2021 15:11:18 +0530
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Hi,

On 8/12/2021 2:37 PM, Felipe Balbi wrote:
> Hi,
>
> (why isn't this email plain/text? Content Type was set to multipart
> alternative, please configure your email client correctly :-)
>
> While at that, also make sure to break lines at 80-columns)
>
> Sandeep Maheswaram <sanm@codeaurora.org> writes:
>> Hi,
>>
>> Earlier I have posted the patch for usb dwc3 core shutdown callback
>>
>> https://lore.kernel.org/linux-arm-msm/1618380209-20114-1-git-send-email-sanm@codeaurora.org/
>>
>> and it was reverted due to issues.
> Right, as should be expected when we find regressions
>
>> https://lore.kernel.org/linux-usb/20210603151742.298243-1-alexandru.elisei@arm.com/
>>
>> As we already have shutdown callback in xhci plat driver where we halt
>> the controller, so there will be no transactions with usb devices.
>>
>> https://lore.kernel.org/linux-usb/20200306092328.41253-1-ran.wang_1@nxp.com/
>>
>> So I think dwc3 core shutdown may not be required at least when we are
>> using host mode. Let me know your opinion about this.
> If that's the case, then sure. Please validate the condition, though,
> and kindly report back on your findings

I have enabled couple of logs in shutdown path and see no URBs enqueued 
after xhci shut down.

Hope this is enough for validation . Please suggest if anything more I 
could do.

[  312.862737] systemd-journald[650]: Received SIGTERM from PID 1 (init).
[  312.866332] xhci-hcd xhci-hcd.0.auto: xhci_urb_enqueue
[  312.875205] xhci-hcd xhci-hcd.0.auto: xhci_urb_enqueue
[  312.951045] Unsafe core_pattern used with fs.suid_dumpable=2.
[  312.951045] Pipe handler or fully qualified core dump path required.
[  312.951045] Set kernel.core_pattern before fs.suid_dumpable.
[  312.981364] ip_local_port_range: prefer different parity for 
start/end values.
[  313.086729] Bluetooth: qca_download_firmware() hci0: QCA Downloading 
qca/crnv32.bin
[  313.194059] init: console-ttyMSM0 main process (516) killed by TERM 
signal
[  313.317109] kvm: exiting hardware virtualization
[  313.338988] platform video-firmware.0: Removing from iommu group 14
[  313.345975] platform wifi-firmware.0: Removing from iommu group 12
[  313.372244] xhci-hcd xhci-hcd.0.auto: -->xhci_shutdown
[  313.377591] xhci-hcd xhci-hcd.0.auto: // Halt the HC
[  313.382811] xhci-hcd xhci-hcd.0.auto: xhci_shutdown completed - 
status = 1
[  313.398238] Bluetooth: qca_uart_setup() hci0: QCA setup on UART is 
completed
[  313.405583] debugfs: Directory 'ibs' with parent 'hci0' already present!
[  313.439006] Bluetooth: qca_hw_error() hci0: mem_dump_status: 0
[  313.445073] Bluetooth: qca_send_crashbuffer() hci0: crash the soc to 
collect controller dump
[  313.595791] arm-smmu 15000000.iommu: disabling translation
[  313.601831] arm-smmu 5040000.iommu: disabling translation
[  313.608559] reboot: Restarting system

Regards

Sandeep