Re: Checking module parameters

From: Nick Craig-Wood
Date: Mon Jan 19 2009 - 05:11:32 EST


David Wagner <daw@xxxxxxxxxxxxxxx> wrote:
> Is there a way to tell what options have been applied to a currently
> loaded kernel module?
>
> I'm trying to force libata to use 1.5Gbps rather than 3Gbps, so I created
> a file /etc/modprobe.d/local containing:
> options libata force=1.5Gbps
> However my SATA drive gets loaded at 3Gbps. I'm trying to figure out how
> to debug this so that I can tell whether the option got correctly applied
> to the libata module, and if not, how to force the SATA link to 1.5Gbps.
> Any suggestions or ideas?
>
> (I can't set libata.force=1.5Gbps as a kernel argument because on my
> Fedora kernel, libata is loaded as a module rather than built into the
> kernel. I can't run "modprobe libata force=1.5Gbps" by hand because
> I've got SATA drives, so the libata module is automatically loaded before
> I get shell access.)

I had to do this recently (under debian I ended up putting
"libata force=1.5Gbps" into /etc/modules)

You can check it is working by looking for something like this in the log

[ 2.345058] ata1: FORCE: PHY spd limit set to 1.5Gbps
[ 2.345058] ata1: SATA max UDMA/133 abar m2048@0xfb106000 port 0xfb106100 irq 218
[ 2.345058] ata2: FORCE: PHY spd limit set to 1.5Gbps
[ 2.345058] ata2: SATA max UDMA/133 abar m2048@0xfb106000 port 0xfb106180 irq 218
[ 2.345058] ata3: FORCE: PHY spd limit set to 1.5Gbps
[ 2.345058] ata3: SATA max UDMA/133 abar m2048@0xfb106000 port 0xfb106200 irq 218
[ 2.345058] ata4: FORCE: PHY spd limit set to 1.5Gbps
[ 2.345058] ata4: SATA max UDMA/133 abar m2048@0xfb106000 port 0xfb106280 irq 218
[ 2.345058] ata5: FORCE: PHY spd limit set to 1.5Gbps
[ 2.345058] ata5: SATA max UDMA/133 abar m2048@0xfb106000 port 0xfb106300 irq 218
[ 2.345058] ata6: FORCE: PHY spd limit set to 1.5Gbps
[ 2.345058] ata6: SATA max UDMA/133 abar m2048@0xfb106000 port 0xfb106380 irq 218

--
Nick Craig-Wood <nick@xxxxxxxxxxxxxx> -- http://www.craig-wood.com/nick
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