Messages in this thread | | | Date | Wed, 1 Mar 2006 23:34:30 +0100 | From | Olivier Galibert <> | Subject | Re: MAX_USBFS_BUFFER_SIZE |
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On Wed, Mar 01, 2006 at 01:54:23PM -0800, Greg KH wrote: > On Wed, Mar 01, 2006 at 10:42:35PM +0100, Ren? Rebe wrote: > > So, queing alot URBs is the recommended way to sustain the bus? Allowing > > way bigger buffers will not be realistic? > > 16Kb is "way big" in the USB scheme of things aready. Look at the size > of your endpoint. It's probably _very_ small compared to that. So no, > larger buffer sizes is not realistic at all.
As a data point, I have traces of a scanner session including a download of a 26Mb binary image using 524288 bytes logical blocks physically transferred with 61440 bytes bulk_in frames. Seems stable enough. IIRC the scanner-side controller chip has some advanced buffering just to handle that kind of bandwidth.
ISTR a preliminary linux userland driver using libusb having problems keeping up with the scanner too. May very well have been an issue with the driver itself though, so I wouldn't read too much into that.
OG.
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