Re: [RFT PATCH 1/4] usb: dwc2: Simplify and fix DMA alignment code

From: Antti SeppÃlÃ
Date: Sat Feb 29 2020 - 11:34:16 EST


On Sat, 29 Feb 2020 at 17:25, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> Sigh. It would have been too simple. Too bad I can't test myself.
> I'd like to know if this is because URB_NO_TRANSFER_DMA_MAP is set on a
> transfer, or because the beginning of the buffer indeed needs to be aligned
> to the DMA cache line size on that system. In the latter case, the question
> is why the alignment to DWC2_USB_DMA_ALIGN (=4) works. In the former case,
> question would be why the realignment does any good in the first place.
>
> Any chance you can add some test code to help figuring out what exactly
> goes wrong ?
>

Sure, I can try to help. Just let me know what code you would like to
insert and where and I'll see what I can do.

--
Antti