Re: HEADS UP: Check your devices' UDMA settings - *TEMPORARY* *WORKAROUND*

On Wed, 2011-04-06 at 15:04 +1000, Basil Chupin wrote:
On 05/04/2011 15:51, Basil Chupin wrote:
It appears that Bug #195221 has suddenly come back -- see

This bug re-appeared on 1 April (my time, Australia, East Coast)
because the previous day my logs showed that the UDMAs were being set
correctly. The only thing which I can see is that on 1 April there was
a kernel firmware upgrade but as I know nuffin' about kernels (or
majors or even captains) this upgrade may have nothing to do with it.

What the above Bug is about is that even though your HDD, for example,
can do UDMA 133 the UDMA in fact gets set to UDMA 33 because some
check concludes incorrectly that the device is connected with a
40-wire cable. Here is an example I just took from my dmesg log file:


The temporary workaround for this problem is to add to the boot
parameters the following: libata.force=X:80c

where X is the IDE line which is being affected by this UDMA problem. In
my case, the devices on line #2 are affected so I use libata.force=2:80c
and now the HDD and the DVDRW are being set to UDMA 100 & 100, respectively.

Using 'libata.force=X:80c' is working because libata is actually
statically embedded in the kernel; if it was not then you would use

(Now I have to go and read up on grub 2 to see how I can insert this
workaround in grub without having to add this everything to the boot
parameters at boot time.)

Glad to see you beat that bugger-bear! Man, it has been an uphill climb
for you to get this far. I tip my wayward4now hat at ya! :) Ric

My father, Victor Moore (Vic) used to say:
"There are two Great Sins in the world...
..the Sin of Ignorance, and the Sin of Stupidity.
Only the former may be overcome." R.I.P. Dad.
Linux user# 44256

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