Re: Regarding usb dwc3 core shutdown callback

Hi,

On 8/26/2021 4:13 PM, Felipe Balbi wrote:

Hi,

Sandeep Maheswaram [off-list ref] writes:

quoted

quoted

(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 [off-list ref] writes:

quoted

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/ (local)

and it was reverted due to issues.

Right, as should be expected when we find regressions

quoted

https://lore.kernel.org/linux-usb/20210603151742.298243-1-alexandru.elisei@arm.com/ (local)

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/ (local)

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.

how about writing a little script to kexec into another kernel for a few
hundred iterations and make sure things still work after all that?

Currently kexec is not supported on qcom devices.  Anything we can do 
apart from kexec?