On Mon, 28 Feb 2005, David Brownell wrote: > On Sunday 27 February 2005 5:16 pm, Gerd v. Egidy wrote: > > > >> usb-storage: usb_stor_bulk_transfer_sglist: xfer 131072 bytes, 17 entries > > usb-storage: Status code -121; transferred 130061/131072 > > usb-storage: -- short read transfer > > usb-storage: Bulk data transfer result 0x1 > > usb-storage: Attempting to get CSW... > > usb-storage: usb_stor_bulk_transfer_buf: xfer 13 bytes > > usb-storage: command_abort called > > usb-storage: usb_stor_stop_transport called > > usb-storage: -- cancelling URB > > usb-storage: Status code -104; transferred 0/13 > > usb-storage: -- transfer cancelled > > usb-storage: Bulk status result = 4 > > usb-storage: -- command was aborted > > That's interesting. Basically the device sent 13 bytes less than 128KB.
Actually it sent 13 bytes more than 127 KB. > And 13 bytes is the sise of a CSW ... as if it has only 128KB of buffer > space, and 13 bytes at the end is tied up for the CSW. But absolutely > unlike any failure that the EHCI driver would trigger; those would all > kick in at 512 byte boundaries. It certainly seems likely that the extra 13 bytes is somehow related to the size of a CSW. But numerology is never very convincing. If 128 KB was the limit, why wouldn't the device send 255 512-byte packets (i.e., 127.5 KB) before the short 13-byte packet? > Maybe it'd be happier with a slightly shorter read? Could be. Gerd, have you changed the max_sectors value associated with the device? The default value used by usb-storage is 240, which corresponds to a maximum transfer length of 120 KB. But your log shows attempted transfers of length 128 KB -- perhaps that sometimes causes trouble. Hmmm... Maybe the block layer isn't honoring max_sectors any more... Incidentally, I filed a technical support request with Cypress Semiconductors about this. Maybe they'll be able to help... Alan Stern ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
