[ltp] after ejecting ultrabay, how to insert new disk ?

[John Lumby]

I have kernel 2.6.13.4 with ACPI_IBM built-in, and hdparm 6.1, running on an 
IBM T42 (2373-KYU).     With this I can eject the ultrabay and then use 
hdparm to unregister the device.    I would like to be able to then insert a 
new disk and register it but can't get that to work.   I'm not even sure 
whether that is supposed to be possible or not.

Here's my ide config as reported by dmesg:
dmesg|fgrep ide
BIOS-provided physical RAM map:
CPU: After generic identify, caps: afe9f9bf 00000000 00000000 00000000 
00000180 00000000 00000000
CPU: After vendor identify, caps: afe9f9bf 00000000 00000000 00000000 
00000180 00000000 00000000
Boot video device is 0000:01:00.0
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
    ide0: BM-DMA at 0x1860-0x1867, BIOS settings: hda:DMA, hdb:pio
    ide1: BM-DMA at 0x1868-0x186f, BIOS settings: hdc:DMA, hdd:pio
Probing IDE interface ide0...
ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
Probing IDE interface ide1...
ide1 at 0x170-0x177,0x376 on irq 15
ide-floppy driver 0.99.newide

Here's what I tried:
hdparm -U 1 /dev/hdc

/dev/hdc:
attempting to unregister hwif#1


----   here I pulled device out and then re-inserted   -------

hdparm -R 0x170 0 0 /dev/hdc
/dev/hdc: No such device or address

so then I have nothing driving /dev/hdc and can't get it back.

If I try this but without first unregistering, then any attempt to refer to 
/dev/hdc afterwards results in the system freezing.

Can someone describe how to get a new device registred on the ide?

John