Re: [Bug 220748] usb: xhci_queue_isoc_tx_prepare ignore start_frame and always assumes URB_ISO_ASAP is set

[Alan Stern <stern@rowland.harvard.edu>]

On Thu, May 07, 2026 at 11:54:32PM +0200, Michal Pecio wrote:
> Alan pointed out that kerneldocs are more up to date, but there is
> still a crucial error there: on ehci-hcd, an URB submitted too late
> completes with -EXDEV instead of the submission failing with -EXDEV.

I don't remember the details exactly, but are you perhaps not taking 
care to distinguish between URBs that are partially too late (some of 
their packets' time slots have expired but some have not) and URBs that 
are entirely too late (all of their packets' time slots are expired)?

As I recall, the first case is supposed to complete with some of the 
packet statuses set to -EXDEV, whereas in the second case the entire 
submission is supposed to fail with -EXDEV.

But my memory could easily be wrong.  And I'm too tired to check the 
source code now...

Alan Stern