On Wed, 22 Nov 2006, Andrew Morton wrote: > Begin forwarded message: > > Date: Wed, 22 Nov 2006 11:53:22 +0100 > From: DervishD <[EMAIL PROTECTED]> > To: Linux-kernel <linux-kernel@vger.kernel.org> > Subject: usb-storage data errors > > > Hi all :) > > I'm having a problem with usb-storage devices under: > > - Two different kernels: 2.4.31 (vanilla) and 2.6.17 (Ubuntu). > - Two different USB 2.0 cards (ALi chipset and VIA chipset). > - So, two different drivers (OHCI and EHCI). > - Two different usb-storage adapters (an external USB box from an > unknown manufacturer and Conceptronic CIDE23U). Both are > USB-to-IDE adapters. > - Many different hard disks. > - Both vfat and ext2/3 filesystems. > - Perfect RAM (at least, that's what memtest says). > - Correctly cooled system. > > The problem is the following: whenever I copy a lot of data to > the usb-storage device (more than a few GB's), the copy goes OK, > without an error, but when I compare the copied files with the > original files, sometimes a copied file is different. This does not > happen if I copy the files one by one, and it doesn't happens all the > time, sometimes the copy is perfect.
Intermittent problems like this are very hard to track down. It sounds like a hardware problem of some sort, but without more information it's impossible to say if the problem lies in your computer, the USB cable, the USB-storage adapters, or the hard disk drives. Have you tried using different cables? > In addition to this, from time to time the usb-storage adapters > (any of them, with any of the USB cards and any kernel) report a read > error, telling that some sector could not be read. This is false > because if I repeat the operation, the sector is correctly retrieved. No, the messages are not false. They definitely indicate a problem; you mustn't dismiss them so easily. With borderline hardware it's entirely possible that an operation can fail at moment and then succeed a few moments later. > This can be related to some kind of timing problem, I don't know. > > The fact is that I cannot reproduce the problem reliably, so I > cannot give you a "recipe", except that it happens when I copy a lot > of data at a time. > > Any suggestion about how to narrow the problem down? Any more > data that you may need? A known bug? Am I doing any stupidity? Well, you could start by posting some of the error messages! Also, it wouldn't hurt to turn on CONFIG_USB_DEBUG and rebuild the USB drivers in your kernel, then post the entire kernel log starting from when you plug in the drive. It's impossible to tell whether your problem is due to a known bug without more information. About all you've told us so far is that from time to time something goes wrong. That's not much to go on. 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-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
