I have a new (2005) Zio 10-in-1 card USB2.0 reader. When I plugged it in for the first time, everything worked:

kernel: hub.c: new USB device 00:03.3-1, assigned address 2
kernel: usb.c: USB device 2 (vend/prod 0xdda/0x1) is not claimed by any active driver.
/etc/hotplug/usb.agent: Setup usb-storage for USB product dda/1/15b
kernel: Initializing USB Mass Storage driver...
kernel: usb.c: registered new driver usb-storage
kernel: scsi1 : SCSI emulation for USB Mass Storage devices
kernel: Vendor: Zio Corp Model: CF Card CF Rev: 1.5B
kernel: Type: Direct-Access ANSI SCSI revision: 02
kernel: Vendor: Zio Corp Model: Multi Card MS Rev: 1.5B
kernel: Type: Direct-Access ANSI SCSI revision: 02
kernel: USB Mass Storage support registered.
kernel: Attached scsi removable disk sda at scsi1, channel 0, id 0, lun 0
kernel: Attached scsi removable disk sdb at scsi1, channel 0, id 0, lun 1
kernel: SCSI device sda: 503808 512-byte hdwr sectors (258 MB)
kernel: sda: Write Protect is off
kernel: sda: sda1
kernel: sdb: Unit Not Ready, sense:
kernel: Info fld=0x0, Current 00:00: sense key Not Ready
kernel: Additional sense indicates Medium not present
kernel: sdb : READ CAPACITY failed.
kernel: sdb : status = 1, message = 00, host = 0, driver = 08
kernel: Info fld=0x0, Current sd00:00: sense key Not Ready
kernel: Additional sense indicates Medium not present
kernel: sdb : block size assumed to be 512 bytes, disk size 1GB.
kernel: sdb: I/O error: dev 08:10, sector 0
kernel: I/O error: dev 08:10, sector 0
kernel: unable to read partition table
kernel: usb.c: USB disconnect on device 00:03.3-1 address 2

I have CONFIG_SCSI_MULTI_LUN set in my kernel options, so I can see the second slot as well. As you can see from the above kernel log, I have a 256MB card mounted in the CF slot on plugging it in (sda), and nothing in the second (SD/SmartMedia) slot (sdb). My fstab contains:

/dev/sda1 /mnt/usb vfat noauto,user,rw 0 0

and everything works. But I can only do this ONCE. If I unmount, unplug, then plug back in again (with the card still in the CF slot), the log looks like this:

kernel: hub.c: new USB device 00:03.3-1, assigned address 3
/etc/hotplug/usb.agent: Setup usb-storage for USB product dda/1/15b
kernel: sda: Unit Not Ready, sense:
kernel: Info fld=0x0, Current 00:00: sense key Not Ready
kernel: Additional sense indicates Medium not present
kernel: sda : READ CAPACITY failed.
kernel: sda : status = 1, message = 00, host = 0, driver = 08
kernel: Info fld=0x0, Current sd00:00: sense key Not Ready
kernel: Additional sense indicates Medium not present
kernel: sda : block size assumed to be 512 bytes, disk size 1GB.
kernel: sda: Write Protect is off
kernel: sda: I/O error: dev 08:00, sector 0
kernel: I/O error: dev 08:00, sector 0
kernel: unable to read partition table

and I cannot mount it again, with the error "/dev/sda1 is not a valid block device". And whatever happened to sdb, the second (SD/SmartMedia) slot? I can get it all to work again by doing rmmod/insmod usb-storage (as root) but that's nasty. My Freecom USB hard disk works fine any number of times - the problem is only with the Zio reader. Has anyone managed to ger a card reader to mount repeatedly without doing rmmod/insmod usb-storage?

OS: RH8.0
Kernel: 2.4.26
USB chipset: Silicon Integrated Systems [SiS] USB 1.0 Controller
USB2.0 chipset: Silicon Integrated Systems [SiS] USB 2.0 Controller

I have discovered a simple work-around: I just leave the reader plugged in all the time, then I just:
1. ensure spare card in slot at boot (a useless old 8MB card!),
2. to use, remove spare card, insert desired card,
3. mount, use card,
4. umount, remove card, reinsert spare card.

Seems to work - it was nice to be able to disconnect the reader so my desk isn't so cluttered, but it not a big problem. I'm upgrading to FC3 this week, so things might improve (or not!).

Upgraede to FC3 and all the problems went away. FC3 rocks!

That's "upgraded".