On Fri, 26 Aug 2005, pat kennedy wrote: > Has anyone experienced this. I have RHES3 on a dell > 2850. I have connected 4 Toshiba dvd readers through > a usb hub, and configured hotplug. All devices look > to be created and I can access the first 3, but the 4 > fails with "no medium found". > > --/etc/fstab entries-- > /dev/cdrom1 /mnt/cdrom1 udf,iso9660 > noauto,owner,kudzu,ro 0 0 > /dev/cdrom2 /mnt/cdrom2 udf,iso9660 > noauto,owner,kudzu,ro 0 0 > /dev/cdrom3 /mnt/cdrom3 udf,iso9660 > noauto,owner,kudzu,ro 0 0 > /dev/cdrom4 /mnt/cdrom4 udf,iso9660 > noauto,owner,kudzu,ro 0 0 > > The dmesg shows from when I plug the hub in. It > detects all 4 cdroms, but when I try to mount > /mnt/cdrom4 I get the "cdrom: open failed". I then > mount the other 3 cdroms with no problem.
Unfortunately the debugging facilities in the usb-storage driver aren't well suited to solving this kind of problem. (By the way, someone else reported a similar problem a few months ago; I don't think it ever got solved.) Here's what you can do to improve the situation. First, turn on USB Mass Storage verbose debugging in the kernel configuration (CONFIG_USB_STORAGE_DEBUG) and rebuild the usb-storage driver. Second, unplug the fourth DVD reader from the hub before starting up, and wait for the system to finish detecting and mounting the first three drives. Third, plug in the fourth drive, and see if it still has problems mounting. (Don't do anything that would cause activity on the first three drives during this time.) Post the dmesg log showing what happens when you plug in and try to mount the fourth drive. Oh yes, if you run HAL, it will simplify the debugging if you turn off the hald program while conducting this test. Alan Stern ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
