New subject: [opensuse-kernel] PATA devices being configured with wrong UDMA

25 May 2011

      -------- Original Message --------
Subject: 	Re: [opensuse-kernel] PATA devices being configured with wrong 
UDMA
Date: 	Mon, 23 May 2011 17:47:48 +1000
From: 	Basil Chupin 
To: 	opensuse-kernel@opensuse.org

On 21/05/11 01:35, Jean Delvare wrote:
...
Hi Basil,
Le vendredi 20 mai 2011 16:36, Basil Chupin a écrit :
...
(Won't go into reasons, but it has to do with openSUSE and audio and
pulseaudio and getting different results when installing the same copy
of 11.4/KDE on the same system.......but let's not get into this one
right now, OK? :-D .)
Don't tell me about sound and pulseaudio :(
I won't ever again, I promise (until the next time) :-) .
...
More seriously, comparisons like this are very difficult to
establish, and are often biased by personal experience.
Out of curiosity, did you try a different operating system on the
same hardware, to see if it was doing any better with UDMA speed
detection?
I had no intention of this going into some sort of a bun-fight over what 
seems to be a simple matter - and I still have no intention of this 
going into such a state.

I asked a simple question which was about what was the correct format to 
use in the "libata.force" statement to get both PATA channels working 
with an 80-wire cable; to show why I was asking the question I gave an 
extract from the boot.msg log file as well as making the comment that 
this hassle with the kernel incorrectly deciding that the machine was 
using a 40-wire cable has been known since at least 2008.

I received from you the answer as to what was the correct format to use 
for this over-riding kernel parameter. Wonderful! But then the 
(unintended) "fight" started :-D .

To save space and time what I deliberately omitted from my original post 
was that I had the following configuration a couple of weeks before I 
posted my question:

PATA #1 : WD HD with UDMA 133
                 LG CDROM with UDMA 33

PATA #2: Seagate with UDMA 100
                Pioneer DVD-RW UDMA 100

and the kernel was giving me the correct UDMA settings for PATA #1 (UDMA 
133/33) [NOTE: 133/33] *without* any "libata fix" but I had to use 
"libata.force=2:80c" to get the correct UDMA set for PATA #2.

This was all fine until I had to replace the LG CDROM (UDMA 33) with the 
new Pioneer DVD-RW which has UDMA 100.

(And this one is for Stefan: NOTE that the UDMA was set correctly on 
PATA #1 *without* any "libata" fiddles for #1 - so, the chip is working 
fine, right?)

When I did replace the LG CDROM on PATA #1 with a new Pioneer DVD-RW - 
so that I now had the Maxtor UDMA 133 with the DVD-RW UDMA 100 - the 
kernel decided that I had a 40-wire cable connected on PATA #1 and made 
both devices UDMA 33.

PATA #2 was still correctly set (to 100/100) by the entry of 
"libata.force=2:80c".)

This is when I posted my message of help for the correct format of the 
wording to get BOTH channels set to the correct UDMA by the kernel.

Now, 2 things are associated with this:

(1) how did I learn that the kernel required the fiddle of 
"libata.force=..."? because I searched the net and found many references 
to this problem but the one which gave me the most acceptable solution 
(others where to recompile the kernel after setting the appropriate 
parameter already existing in the kernel, and applying a patch to the 
kernel) was the one I found here:

http://viktorbalogh.net/blog/other/libata-workaround-limited-to-udma33-due-t...  
;

(2) why did I ask my question here and not in some "kernel upstream" 
list? I did so because there is a self-appointed "mail list cop" who 
inhabits opensuse help mail list and told me off for asking the question 
about KDE in the opensuse help list but which have been asked in the KDE 
mail list - which meant that "as good little soldier" I should ask my 
question about the kernel in *this* mail list to avoid the wrath of that 
"list cop" :-) . And, secondly, I don't know any "upstream kernel" list 
nor did I think that I needed to do so just to have a simple question 
about the correct wording format to use to get the "fix" working.

My real problem was in adding my comments about this kernel problem 
being known for at least 3 years and for which I shall now go and put on 
my hair-shirt, kneel on a bed of hot ashes and flagellate myself 
for......oh, I don't know - perhaps several nano seconds or so? :-) .

Lastly, you asked if I had this hassle on other distros. The answer is 
YES - and at least one uses a more up-to-date version of the kernel (eg, 
Ubuntu). In all cases the only "libata fix" I had to use was to set PATA 
#2 to be correct, because I still had the LG CDROM on PATA #1 and the 
UDMA for devices on PATA #1 were being set correctly. However, since 
getting the new RW on #1 I have not used the other distros so cannot say 
what the results would be if I did.

(I wouldn't be having this drawn out discussion to justify my 
results/question if I hadn't had to replace the LG CDROM on PATA #1 with 
the Pioneer DVD-RW :'( .

But life wouldn't be so interesting without such little PITAs, would it? 
:-D )

BC

-- 
"The time has been
That, when the brains were out, the man would die,"
                  "Macbeth", Shakespeare

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Fwd: Re: [opensuse-kernel] PATA devices being configured with wrong UDMA

Basil Chupin

Hannes Reinecke

Stefan Seyfried

Jean Delvare

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participants (4)