Hi, > There's a description of max_sectors in the FAQ at www.linux-usb.org. > Can you verify that it is still set to 240? Maybe something we're not > aware of has changed it.
[EMAIL PROTECTED] cat /sys/block/sda/device/max_sectors 256 direct after plugging in. don't know where that comes from. maybe some hotplugging scripts. I can take a look where that is from if that matters. > Also, I just tried doing some usb-storage READs. On my system the > transfer lengths never went above 120 KB. So I'd like to know why it went > up to 128 KB in your test. Suppose you try doing what I did: > > dd if=/dev/sda of=/dev/null bs=64k > Does that cause 128 KB transfers? If not, what did you do to cause them? > It would be great if I could reproduce it here. With dd (on the pure disk, just as in your example) the first reset happens a lot faster than with my method which was running rdiff-backup to a disk with reiserfs ontop of a dm-crypto. Maybe the dd generates more stress on the usb. > The way to reduce the transfer lengths is to decrease max_sectors. At > least, that's how it's _supposed_ to work. I don't think any additional > debugging will help; it's already pretty clear that the device isn't > behaving the way it should. I tried reducing max_sectors to 128 and bs=32k: usb-storage: usb_stor_bulk_transfer_sglist: xfer 65536 bytes, 8 entries usb-storage: Status code -121; transferred 64525/65536 max_sectors 64, bs=16k: usb_stor_bulk_transfer_sglist: xfer 32768 bytes, 8 entries usb-storage: Status code -121; transferred 31757/32768 but even if I set max_sectors to 8 (bs=2k or lower, doesn't matter) the lowest amount of bytes transmitted seems to be always 4k. The errors look like this: usb_stor_bulk_transfer_sglist: xfer 4096 bytes, 1 entries usb-storage: Status code -121; transferred 3085/4096 So in case of an error there are always 1011 bytes missing in the transfer. Kind regards, Gerd ------------------------------------------------------- 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 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
