Red Hat Bugzilla – Bug 141697
ATAPI-CDROM not accessible with kernel options ide-scsi and swiotlb
Last modified: 2007-11-30 17:07:05 EST
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Description of problem:
If the kernel is loaded with the options ide-scsi (to use the atapi
dvd/cd-writer as scsi device) AND swiotlb (for the nvidia driver), the
dvd/cd-drive is not accessible, eg. for mount, eject, cdrecord.
Removing either the ide-scsi option or the swiotlb option, the
dvd/cdrom-drive works as expected.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. boot the kernel with eg. hdc=ide-scsi swiotlb=16384
2. mount /dev/cdrom /mnt/cdrom; eject; cdrecord -scanbus
3. remove one of the options ide-scsi or swiotlb and boot again
4. mount /dev/cdrom /mnt/cdrom; eject;
Actual Results: the dvd/cdrom-drive is not a valid block device for
the mount command, it cannot accessed and used by cdrecord, it cannot
be opend oder closed using the command eject
Expected Results: opening and closing using the command eject
mounting of cds and dvds
writing cds using cdrecord
the option swiotlb is neccessary for the hardware accelerated graphic
driver from nvidia.
Believe it or not, if you reverse the order of the kernel parameters, that is,
change "hdc=ide-scsi swiotlb=16384"
to "swiotlb=16384 hdc=ide-scsi"
I believe you will find the problem does not occur.
Please confirm. We are working on a proper fix.
hda=ide-scsi parameter gets mangled before ide_setup gets ahold of it
> Believe it or not, if you reverse the order of the kernel parameters, that is,
> change "hdc=ide-scsi swiotlb=16384"
> to "swiotlb=16384 hdc=ide-scsi"
I want to believe. ;-)
> I believe you will find the problem does not occur.
> Please confirm. We are working on a proper fix.
Unfortunately, I'm on holidays now, I will check the revers order of the kernel
parameters in january 2005.
The change to increase the default swiotlb to 16384 was committed into
the RHEL3-U5 pool.
This problem has been resolved by making swiotlb=16384 the default setting
for ia32e (EM64T) platforms. Larry Woodman's patch was committed to the
RHEL3 U5 patch pool on 23-Dec-2004 (in kernel version 2.4.21-27.5.EL).
Yep, reversing the order of the kernel parameters works like a charm.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.