I have a dual opteron system with the nvidia nforce pro chipset, and an sata disk. I use 2.4.31 default sata kernel with slackware 10.2 without any problems at all (but I want to use 2.6, and I need to recompile for smp anyway). When I continue to boot the new kernel (2.6.15.2) it seems extremely slow, and it says ata1: "command 0x25 timeout, stat 0x50 host stat 0x24" a couple times (more and more during the boot process), and finally comes to a stop and repeats that about every minute. The boot process gets no further than "found reiserfs 3 file system or whatever", and seems to be stopped by the consistent error mentioned above. I appreciate all help, thanks.

I'm running 2.6.15.2 here fine, but I don't have sata... Maybe you could try backing off a the .2 patch and check if it's something new for 2.6.15.2... Go back to 2.6.15 maybe... Assuming you have the nvidia chipset selected in the config, and nvidia sata...

I don't have all day to try compiling differen kernels, I do know, however, that 2.6.15.1 did the same thing. Do you know what this error means?

I have a feeling that you Opteron compiles a kernel pretty quick, I know my poor ol 2800 does it okay

Not sure what the error means, I was just trying to cover the obvious and see what you set in the kernel config... Maybe a DMA or chipset issue... Or a new bug in the .2 kernel...

Ok, I compiled 2.6.13 this time, and the system froze right away when it got to a similar line as last time:
ata: dev 0 ata UDMA /133 145226112 sectors: lba48

Any ideas on what is happening?

Obviously not a 2.6.15.2 problem anyway, so that's one thing to rule out.

I'm thinking it's something to do with the nforce DMA module... What chipset is that? One of the earlier nforce or more recent? nforce 3 (150/250) or nforce 4? I don't have a sata drive hear yet to do some comparisons, unfortunately

I'm using nforce3 250 chipset...

NVIDIA nForce Professional 2200, 2050 and AMD 8132 chipset. The default 2.4.31 sata with slackware 10.2 worked fine. And by the error, I don't think you can tell its a sata problem...

Can you get a stock slack 2.6 kernel package and try that. If that works then maybe it's something in the kernel config (and you can use the stock config as a start point for the 2.6.15 kernel), if not then maybe it's an issue with that hardware and the 2.6 kernel series...

Ok, I used the .config file from a slackware 10.2 2.6.13 kernel, to compile a kernel.org 2.6.13 kernel from source. This time there seemed to be no sign of the previous error, but I didn't get far due to a kernel panic:
VFS: cannot open root device "802" or unkown block (8,2)
Please append a correct "root=" boot option
Kernel panic- not syncing:VFS: unable to mount root fs on unkown block (8,2)

Sounds like the root filesystem is a module or something. Will have to compile that in to the kernel.