Re: usb: dwc3: gadget: Don't clear flags before transfer ended

[Greg KH <gregkh@linuxfoundation.org>]

On Sat, Apr 18, 2020 at 12:25:16PM +0200, Delio Brignoli wrote:
> Please apply the following commit:
> 
> Commit subject: usb: dwc3: gadget: Don't clear flags before transfer ended
> Commit ID: a114c4ca64bd522aec1790c7e5c60c882f699d8f
> Apply to: at least 4.19 stable, and 5.4 stable if possible. Note that all kernels from v4.18-rc1 up to 5.7-rc1 are affected.
> 
> Why apply it:
> <https://github.com/torvalds/linux/commit/a114c4ca64bd522aec1790c7e5c60c882f699d8f> fixes <https://github.com/torvalds/linux/commit/6d8a019614f3a7630e0a2c1be4bf1cfc23acf56e>. Without this fix the built-in USB function source/sink test module fails to work with isochronous endpoints [1]. A side-effect of setting dep->flags = DWC3_EP_ENABLED; in dwc3_gadget_ep_cleanup_completed_requests() as part of disabling an ep is that a subsequent attempt to enable the endpoint will skip __dwc3_gadget_ep_enable() effectively leaving the ep disabled.
> 
> [1] Our gadget driver on TI AM5729 fails to work exactly like the built-in USB function source/sink test module when switching to alternate interface 1 because of the issue described above.
> 
> TI is currently using 4.19 and 5.4 stable kernels as the basis for their processor SDK kernels for their AM57x SoC and may switch to 5.4 stable at a later time. Thank you.

It does not apply to the 4.19.y kernel tree, can you provide a working
backport of it please so that I can apply it?

thanks,

greg k-h