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

[Nathan Bahn]

On Wed, Apr 6, 2011 at 1:04 AM, Basil Chupin <blchupin at iinet.net.au> wrote:

> On 05/04/2011 15:51, Basil Chupin wrote:
>
>> It appears that Bug #195221 has suddenly come back -- see
>> https://bugs.launchpad.net/ubuntu/+bug/195221.
>>
>> 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:
>>
>>  [pruned]
>
> 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 'force=X:80c'.
>
> (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.)
>
> BC
>
>
> --
> Any experiment in life will be at your own experience.
>



B.C.--

So, if I'm understanding you correctly (a BIG if, admittedly), then S.A.T.A.
hard drives are NOT affected by this bug; is my understanding correct? (and
by the way, thanks that response to my question in the other thread!)

--N.B.
-- 
Please avoid sending me Word or PowerPoint attachments.
See http://www.gnu.org/philosophy/no-word-attachments.html &
http://www.libreoffice.org/ (Nathan Bahn)
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