On Wednesday 25 May 2011 08:19:28 am Basil Chupin wrote:
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 .
If it really wasn't intended, then at least it was very awkward. Claiming that a known kernel bug has been left unfixed for 3 years isn't the best way to avoid replies.
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.
The above contains very interesting technical details, the kind that is needed to actually fix bugs. The only thing missing is the PATA controller vendor and model (PCI IDs.) My summary of the above would be: everything is fine without the Pioneer DVD-RW, but as soon as you connect one such drive, the PATA controller is suddenly unable to detect the cable. So I would diagnose an incompatibility between the PATA controller and the Pioneer DVD-RW. Whether this is a hardware issue or a driver bug, I can't tell. As you said your wife had the same problem, is her system also using a similar Pioneer DVD-RW?
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-udma3 3-due-to-40-wire-cable ;
In this report the person is using driver ata_piix. Is it also your case? And your wife's system as well? It is easiest to get a kernel bug fixed if you are able to figure out the exact set of conditions it takes to reproduce. This will let you find who is responsible for the driver in question, and then give that maintainer a chance to reproduce the problem. Problem reproduction is half way to problem fixing.
(...) Lastly, you asked if I had this hassle on other distros.
This was not my actual question. -- Jean Delvare Suse L3 -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org