Re: Allocating buffers for USB transfers (again)

From: MatÄj Laitl
Date: Thu Aug 11 2011 - 19:30:08 EST

On 11.â8.â2011 Daniel Mack wrote:
> On Thu, Aug 11, 2011 at 8:05 PM, Sarah Sharp
> > Because according to Matej, he applied that patch, plus my patch to
> > reject zero-length buffers[1], and he saw debugging that indicated he
> > *did* see zero-length buffers. Is there any chance your driver might
> > submit a zero-length buffer in the middle of the isochronous URB
> > transfer array?
> Hmm, judging from the code, this can only ever happen if we receive an
> inbound iso frame which has a valid status and an actual_length of
> zero. Also, it was not neccessary to catch this case for EHCI.
> Maetj, does this patch make any difference?

This patch actually makes the sound playback _worse_. Now I get strange
squawks where previously at least first seconds of a song sounded normally.

However, I no longer get "zero length buffer submitted" or that "... Weird."
debug messages, only several megabytes of: (should I post these somewhere?)

xhci_hcd 0000:05:00.0: Giveback URB ffff880114cec000, len = 880, expected =
1000, status = -115
xhci_hcd 0000:05:00.0: Giveback URB ffff880114740000, len = 352, expected =
1000, status = -115
xhci_hcd 0000:05:00.0: underrun event on endpoint

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at