Messages in this thread | | | Date | Sun, 16 Oct 2011 11:10:09 +0200 | From | Johannes Stezenbach <> | Subject | Re: [Patch] Increase USBFS Bulk Transfer size |
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On Sat, Oct 15, 2011 at 03:04:28PM -0400, Alan Stern wrote: > On Sat, 15 Oct 2011, Johannes Stezenbach wrote: > > > What I meant to say is Markus' statement that the device only > > works at a certain transfer size cannot be true since > > this size is not visible to the device via the USB bus. > > That's what I would expect, too. But did you take a look at the usbmon > traces Markus acquired? > > http://marc.info/?l=linux-usb&m=131845614819045&w=2
I glanced at them for 3 seconds, but I cannot be bothered to analyze them in detail. The ASCII usbmon traces don't show full USB packet contents anyway so you can't see if partial MPEG TS packets are missing.
> They aren't completely definitive because the communications between > the computer and the device _before_ the bulk transfers started were > different. However they do clearly show the device working with > 24064-byte transfers and not working with 12288+11776-byte transfers.
The device transfers data in the "not working" case, it's just that the MPEG TS sync byte is not where Markus expects it, which could be explained by a partial MPEG TS packet left in the device's FIFO from previous interaction.
Johannes
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