On Fri, 5 Jan 2007, Uwe Bonnes wrote: > >>>>> "Alan" == Alan Stern <[EMAIL PROTECTED]> writes: > > > Alan> There may be electrical or electromagnetic interference problems > Alan> between the two ports on your computer's USB controller. When > Alan> both ports are in heavy use this could affect the total > Alan> throughput. If you only do I/O to one of the sticks at a time, > Alan> does everything work okay? > > No. The transmission has timeouts too, however much less frequent. It took > me 5 "dd" runs on the 2 GByte stick to get to that point. The next three > runs all had problems with the last run unhampered. > > But I tried the same sticks and similar combinbation of read processes on > the sticks on a thinkpad and observed zero dropouts.With 3 sticks, I got the > disk hroughput up to about 28 MByte and was even seeing DVB-T via a USB > Cinergy T2. > > So either the EPOX board has problems, or the VIA Chipset, or our ehci_hcd > implementation.
Since the VIA chipset is _known_ to have problems, there's no reason to believe anything is wrong with ehci-hcd. > Alan> /* * Time out in seconds for disks and Magneto-opticals (which are > Alan> slower). */ #define SD_TIMEOUT (30 * HZ) #define SD_MOD_TIMEOUT > Alan> (75 * HZ) > > Does this long timeout make sense on a USB stick. No disks to spin up, no > heads to move. True. However Linux has no way of knowing that your device is a USB stick. That is, obviously the system knows it is USB -- but there's no way to tell it isn't an actual disk drive. Alan Stern ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
