Re: [PATCH] usb: gadget: configfs: Add lpm_Ux_disable

From: Thinh Nguyen
Date: Tue May 07 2019 - 14:54:12 EST


Hi Claus,

Claus H. Stovgaard wrote:
> On Tue, 2019-05-07 at 11:09 +0200, Claus H. Stovgaard wrote:
>> When combining dwc3 with an redriver for a USB Type-C device
>> solution, it
>> sometimes have problems with leaving U1/U2 for certain hosts,
>> resulting in
>> link training errors and reconnects. This create an interface via
>> configfs for disabling U1/U2, enabling a workaround for devices based
>> on
>> dwc3.
>>
> Sorry messed up a bit with a missing cover letter.
> This feature relates to Anurag patch [1] and a thread [2] from earlier
>
> Where Anurags patch focus on setting U1/U2 latency in the BOS
> descriptor from the devicetree, this patch focuses on having a configfs
> interface for forcing the UDC (here the dwc3) to not enable U1/U2 and
> reject the SET_SEL(U1/U2).
>
> Looking forward to input.
>
> [1] https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_linux-2Dusb_msg179732.html&d=DwIDaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=u9FYoxKtyhjrGFcyixFYqTjw1ZX0VsG2d8FCmzkTY-w&m=wKdyWmYpbW791LAm7rYwvFYx5E0bjENyXZzHvK4vyFo&s=es7kki6iuLJUp2rJnzP9alXKyfJPNSfyxTVCKKDd_rQ&e=
> [2] https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_linux-2Dusb_msg179393.html&d=DwIDaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=u9FYoxKtyhjrGFcyixFYqTjw1ZX0VsG2d8FCmzkTY-w&m=wKdyWmYpbW791LAm7rYwvFYx5E0bjENyXZzHvK4vyFo&s=cFTmO9wPf7b6TZxFUAAIJM0Z_wM1ttNIc1rct0uR6co&e=
>
>

I'm not sure who will submit the patch to make change to DWC3 for
disabling U1/U2 (Anurag or you), but can you split your patch between
dwc3 and configfs.

Thanks,
Thinh