Re: [alsa-devel] Allocating buffers for USB transfers (again)
On 08/12/2011 01:29 AM, Matěj Laitl wrote:
On 11. 8. 2011 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
Might be the hardware doesn't like this. As I said, the patch is blindly written and I couldn't test it. Did you test this on a EHCI port as well?
Daniel
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Daniel Mack