Red Hat Bugzilla – Bug 247350
kernel boot parameter libata.pata_dma=0 does not work in kernel-2.6.21-1.3255.fc7
Last modified: 2008-01-09 12:22:37 EST
Description of problem:
Disabling DMA for PATA optical drives does not work in F7
Version-Release number of selected component (if applicable):
put libata.pata_dma=0 parameter on kernel boot line in grub.conf
Unknown boot option `libata.pata_dma=0': ignoring
have a PATA DVD in PIO mode
Please try "pata_dma=0"
After I boot with pata_dma=0 parameter I don't have again the message "Unknown
boot option ...". However DMA is not disabled for PATA optical device.
After more findings I found out that what work is to put the following line
"options libata pata_dma=0" in /etc/modprobe.conf, remake initrd image and boot
with new initrd.
I'm reviewing this bug as part of the kernel bug triage project, an attempt to
isolate current bugs in the fedora kernel.
This bug appears to be resolved and I am therefore closing it. If I have erred,
please forgive me and re-open with any additional information you are able to
give. I will then try and assist you if I can.
No, this bug is not fixed in kernel kernel-184.108.40.206-76.fc7 (neither in
Okay, sorry to hear it Mihai. However you will be glad to read the following:
therefore I would be grateful if you could test with a rawhide kernel and report
The new pata_dma patch is also in F7 kernel 220.127.116.11-81, which is now in the
Mihai, can you test please and close if fixed for you.
Sorry neither F7 kernel 18.104.22.168-81 from updates-testing repository does not work.
I will try a rawhide kernel as soon as I can.
The same with last rawhide kernel 2.6.23-0.185.rc6.git7.fc8
In what way do these not work? The bug was filed indicates that the boot parameter:
does not work. Is this really still the case?
Apparently you need to add the parameter to the module when it gets loaded, like
in comment #2. This makes it pretty useless for distro installs unless libata is
built into the kernel...
Ref comment #10: yes the bug is still present in all that kernels
Ref comment #11: also this is problem if you want to upgrade firmware for a DVD
with a LiveCD/LiveDVD booted externally
Yeah, without support in anaconda this parameter is pretty much useless. And
since upstream hasn't decided exactly how it will work yet, it should probably
just be removed.
This option was made available for F8 release final with support for anaconda. I
am therefore closing this bug to reflect that. Please re-open if current kernels
do not perform correctly for you.
Also, the option is now "libata.dma" instead of "libata.pata_dma".