On 2009-09-19 15:28 +0800, Eric Ding indited: > On 2009-09-19 04:10 +0800, Alan Stern indited: >> On Fri, 18 Sep 2009, Eric Ding wrote: >> >>> On 2009-09-17 21:38 +0800, Alan Stern indited: >>>> On Thu, 17 Sep 2009, Eric Ding wrote: >>>> >>>>> I'm using the mainline 2.6.31 kernel with an Olympus MAUSB-200 USB xD-Picture >>>>> Card reader and my Olympus 1GB Type H xD-Picture Card, and have had consistent >>>>> problems trying to access and use the card on my Linux system. This card >>>>> (reader) works perfectly fine with my Fujifilm F20 digicam and on my Windows XP >>>>> system, but on my Linux system, the usb-storage driver seems to have problems >>>>> even getting partition information for it. >>>>> >>> [original report trimmed] >>>>> I've included the output of lsusb -v and output from dmesg below. >>>> There isn't enough information in the log to tell what's wrong. We >>>> need to see a usbmon trace showing what happens when you plug the card >>>> reader in. >>> No sweat, see below! Thanks again... >> The trace shows that the card has 2048000 sectors. A bunch of reads >> take place successfully (including a read of the very last sector). >> Then the following happens: >> > [analysis clipped] >> As for why it works under Windows, I can only guess it's because >> Windows doesn't try to read 64 sectors starting at sector 2047768. >> Perhaps if some Windows program tried to do so, the same failure would >> happen. >> >> Probably the Linux program that does the offending read is udev's >> vol_id. If you disable that then perhaps the reader won't crash. > > Hmm... I'm not too familiar with the inner workings of udev, but here's > what I have tried so far: > > 1) Comment out all lines in /lib/udev/rules.d files that refer to > vol_id. Errors still occur. If I look further, it appears that > hald-probe-volume is running while errors are popping up, so I conclude > that hald-probe-volume is provoking this error. So next, I... > > 2) Turn off udev daemon altogether. This eliminates the error, and I can > now manually mount /dev/sdb1 and read/write files to and from the card reader. > > OK, so now I've concluded that the way udev and hald interact with my USB > card reader tickle this bug/issue in my card (reader). I suspect I'm > wandering outside the domain of this list, since it seems you're implying > that there's no kernel workaround for this bug. So now what? Is there a > way to tell hald/udev to treat this device specially and not probe it in > this way? Or is there some kind of a kernel workaround I could try? Just to follow up: I browsed the source code of udev and did a *lot* of trial-and-error playing around with vol_id, and have stumbled on what I cautiously will call a successful workaround. It appears that the part of vol_id which probes for RAID filesystem types is causing the problem... since I don't use RAID at all (and certainly not on my memory card!), I passed the --skip-raid argument to vol_id, and now everything seems to work... for now. A glance at the development sources for udev suggests that vol_id will soon be deprecated, and blkid from e2fsprogs will be used instead. Hopefully that will mean no more workaround in the future, rather than a need for a whole new workaround. :) Thanks, Eric -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
