Created attachment 499096 [details]
screenshot

Description of problem:
rhel4.9 guest cannot find cdrom device after boot up(50% reproduce).

# dd if=/dev/cdrom of=/dev/null bs=1024 count=100
dd: opening `/dev/cdrom': No medium found

# ls -al /dev/cdrom 
lrwxrwxrwx  1 root root 3 May 16 03:53 /dev/cdrom -> hdc

Version-Release number of selected component (if applicable):
host:
kernel 2.6.18-259.el5
kvm-83-232.el5
guest:
kernel 2.6.9-100.ELsmp

How reproducible:
50%

Steps to Reproduce:
1. boot up rhel4.9 guest with cmd
* * * *  cmd * * * * *
# /usr/libexec/qemu-kvm -drive file='RHEL-4.9-32.raw',index=0,if=ide,media=disk,cache=none,format=raw -net nic,vlan=0,model=virtio,macaddr='9a:e3:8e:79:d8:33' -net tap,vlan=0,ifname='t0-174007-A8sb',script='/usr/local/staf/test/RHEV/kvm/autotest-devel/client/tests/kvm/scripts/qemu-ifup-switch',downscript='no' -m 4096 -smp 2,cores=1,threads=1,sockets=2 -drive file='/tmp/orig.iso',media=cdrom,index=1 -cpu qemu64,+sse2 -soundhw ac97 -spice port=8000,disable-ticketing -qxl 1 -rtc-td-hack -M rhel5.6.0 -boot c  -usbdevice tablet -no-kvm-pit-reinjection -monitor stdio
* * * * * * * * * * * *
2. run "dd if=/dev/cdrom of=/dev/null bs=1024 count=100"
  
Actual results:
return message: 
dd: opening `/dev/cdrom': No medium found

Expected results:
could find the cdrom device

Additional info:
Attached the dmesg & /var/log/messages log