Re: [PATCH 1/1] TX throttling bug-fixing patch of AX88179_178A

Ben Hutchings
2013-07-25T15:00:40Z

On Thu, 2013-07-25 at 22:52 +0800, Ming Lei wrote:
[...]
> On Thu, Jul 25, 2013 at 9:34 PM, Ben Hutchings
> <bhutchings@solarflare.com> wrote:
> >
> > Not that I have any experience with USB drivers, but perhaps
> > usb_sg_init()?
>
> USB SG library doesn't support submitting SG URB asynchronously, but that isn't
> a big deal. The problem is that many USB host controllers can't build
> one single
> packet from two buffers, what is why USB stack requires size of all
> buffers(except
> for last one) in sg list can be divided by max endpoint packet
> size.(1024 for usbnet)

Ugh. Maybe the USB stack should allow drivers to find out about and
take advantage of a more flexible host controller. Sounds like it could
be a big job, though.

Ben. (glad not to be using any USB net devices)

--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.