Passing options to modules loaded in initrd

[fabbo]

I have a HD which does not work in Linux unless the option dma=0 is passed to libata.ko.

So, I tried adding libata.dma=0 to the GRUB command line. Nothing.

After booting with the rescue DVD (which uses Isolinux for boot, and that seems to accept libata.dma=0), I discovered that the init script in the initrd image loads libata.ko with insmod, without passing any argument to it. Irrespective of the kernel command line.

Is there a way to pass command line options to modules loaded in initrd? Without having to rebuild the whole initrd, of course.

[jcliburn]

Try adding this line to /etc/modprobe.conf:

options libata dma=0

[fabbo]

Originally Posted by jcliburn

Try adding this line to /etc/modprobe.conf:

options libata dma=0

The problem is that, without loading libata, it won't mount the filesystem from the HD, and therefore it won't even read /etc/modprobe.conf from the HD... It's a chicken and egg problem.

Adding that line, and then rebuilding the initrd, is the solution I'm using now (mkinitrd reads the options lines from modprobe.conf, so it builds an initrd which passes the parameter). But, after a kernel update, the initrd needs to be rebuilt again...

[jcliburn]

Each time you upgrade your kernel, a new initrd will be built automatically that includes your modprobe.conf customizations. You shouldn't have to change anything again.

[fabbo]

OK, I'll try that at the next kernel update.

That makes another question come out. When installing Fedora for the first time, is the initrd generated on the fly, or is it copied from the installation CD?

In the first case, the user, when he is requested to add other kernel parameters, could be also requested for module parameters. So, the right module parameters are present in the initrd since the first install.

[jcliburn]

Originally Posted by fabbo

That makes another question come out. When installing Fedora for the first time, is the initrd generated on the fly, or is it copied from the installation CD?

It's generated on the fly during installation.

In the first case, the user, when he is requested to add other kernel parameters, could be also requested for module parameters. So, the right module parameters are present in the initrd since the first install.

Good idea. You might consider filing a feature request against anaconda at redhat.bugzilla.com.