Re: Kernel 2.6.30rc7 limits IDE to UDMA33

[Grozdan <neutrino8@gmail.com>]

2009/6/5 Alan Cox <alan@lxorguk.ukuu.org.uk>:
>> older kernels have no problems setting the correct UDMA while 2.6.30
>> does have problems. Something must have definitely changed in this
>> latest kernel. I'll go dig in my BIOS to see if I may need to
>> change/force something.
>
> Unless you can actually work through the various kernels and release
> candidates to find the one it changes its basically impossible to tell
> what has occurred or why.
>

Well, I looked around in the BIOS and there isn't anything I can do to
force a specific UDMA - it only offers disable and auto detect.
Upgrading the BIOS firware won't do a thing since I'm already running
the latest version of it. The BIOS correctly reports that my first
disk is using Transfer Mode 6 and my second one Transfer Mode 5. I've
also noticed that some Ubuntu users have the same problem on kernel
2.6.27 (which works for me)

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/285595

So if this can't be fixed in the kernel itself, I may need to resort
to kernel params if I experience the problem again in the future. I
may give all rc's of 2.6.30 a try and see which one introduces it...