Re: [RFT PATCH] xhci: fix frame id calculation for isoc transfer

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 5/11/26 22:21, Mathias Nyman wrote:
> Always calculate estimated start frame, and set urb->start_frame
> 
> Fix valid frame window start and end calculation to match xhci
> spec 4.11.2.5
> 
> Don't inclease frame id with 1 if a URB mod transfer is queued late.
> Queue it with next expected frame ID but print a message if URB is
> next expected frame id does not fir valid frame window range (URB mid
> transfer is queued late)
> 
> This patch doesn't switch to URB_ISO_ASAP /SIA scheduling if URB is queued
> late, not sure if that would help as it only moves the frame id glitch
> problem forward, unless _every_ URB queued after a late URB is forced to
> use SIA, which again would defeat the point of Frame ID use.
> 
> get rid of the annoying 'xep' and 'xdev' variables, xhci driver uses
> ep and vdev naming everywhere else
> 
> Contains some FIXMEs, patch for initial testing purposes
> 
> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> ---

Butchered the commit message but code should be testable

First URB is aligned to full frame, or to interval start if interval is longer
than a frame

For urbs queued mid isoch transfer we check if the next expected frame id
is withinh the accepted frame window, but only print a message if not.
It doesn't alter the expected start frame id, or switch to URB_ISO_ASAP/SIA
scheduling if the check fails.

Always calculate and set urb->start_frame.

URBs with intrval less than a frame do not need to be aligned to entire frame,
next urb can continue mid frame.

-Mathias