Re: [PATCH 1/2] usb: xhci: fix isoc silent reschedule creating stream gap on CFC controllers

[Alan Stern]

On Wed, May 06, 2026 at 03:55:27PM -0400, Dylan Robinson wrote:
> On 5/5/26 16:32, Mathias Nyman wrote:
> > Agreed, setting start_frame to start_frame_id + 1 would only make sense for the very first URB, otherwise we create glitches.
> >
> > Looks like the whole start_frame_id calculation is incorrect.
> 
> I'd also like to call attention to the fact that index in
> xhci_get_isoc_frame_id() refers to the isoc packet index within the
> URB, not the position of the transfer in the overall stream. A driver
> could (although probably shouldn't) submit multiple URBs, each
> describing less than a microframe's worth of transfers, ...

How can this happen?  The only way for an URB to describe less than a 
microframe's worth of transactions is if it describes no transactions at 
all.

Did you mean less than a frame's worth?

Alan Stern