On Sun, 20 Feb 2005, Gerd v. Egidy wrote: > Hi, > > I use a usb-ide enclosure for backup. The enclosure has a cypress chip: > > T: Bus=01 Lev=01 Prnt=01 Port=03 Cnt=01 Dev#= 2 Spd=480 MxCh= 0 > D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 > P: Vendor=04b4 ProdID=6830 Rev= 0.01 > S: Manufacturer=Cypress Semiconductor > S: Product=USB2.0 Storage Device > S: SerialNumber=DEF1076A66AF > C:* #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr= 0mA > I: If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage > E: Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms > E: Ad=88(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms > > During backup the speed is inconsistent: most of the time it is ok but all > 10-20 secs the backup comes to halt. In top(1) I can see that the percentage > used for iowait goes up to 99% during this time. After a few seconds iowait > drops back to <10% and the backup continues. > > Often the backup is aborted after a few hours with a device disconnect and > a oops (see below). > > I tried this with 2.6.11-rc4-bk6 and some other 2.6.11-rc kernels. > > This happens just on one machine, on another machine with identical mainboard, > identical usb-controller and the same disk/enclosure this does not happen. > The only thing that is different is that the machine where it is working has > a slower cpu (Celeron 650 instead PIII 1GHz) and less RAM. > > Both machines were otherwise working stable with a longer uptime (>14 days). > > So I think it might be a timing issue (not the oops but the problems before). > I already tried adding the 110usec delay that the Genesys devices need but > that didn't help. > > Can anyone help making my backup reliable?
This feels like a signal-quality issue. Maybe there's just more electromagnetic noise near the motherboard with the PIII processor, or a bad cable connection... Or maybe I'm totally wrong and the problem is something else entirely. Regardless, I don't know what can be done to eliminate those errors you see. However, the experimental patch in this message http://marc.theaimsgroup.com/?l=linux-usb-devel&m=110876266420588&w=2 ought to help your system recover more quickly and more reliably when the errors occur. As for the oops you saw at the end of your log, there's a series of patches that have already been submitted which should prevent it. However, if the errors are handled more gracefully then you'll probably find that the oops never gets triggered anyway. 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 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
