VIA chipset enabing DMA
 

OK, so I posted another thread asking for suggestions on improving my system performance with 64MB RAM. So upon further investigation in the various log files I realized that since switching to a VIA Apollo Pro 133A based motherboard, my hard drives no long have DMA mode enabled. Specifically, in /var/log/dmesg I get:

VP_IDE: Neither IDE port enabled (BIOS)

Now of course this is wrong, otherwise I wouldn't be able to boot into Linux in the first place!! This is with a new 2.6.7 kernel I just compiled. And yes, I did compile the chipset module as well as IDE options for DMA. The VIA82cxxx module is also installed and loaded.

Just to try things out I booted up a 2.4 kernel I had saved, basically the kernel that I installed off the Debian distro discs. That one worked no problem, DMA was enabled and everything.

So I have a couple of ideas as to why this is happening and I asm hoping people here can shed some light on this. First of all I have a problem with kernel modules at boot time; that is, in /var/log/messages I get a line that says:

No modules symbols loaded - Kernel modules not enabled.

With the 2.4 kernel I don't have this problem, and during bootup the system goes through a process of calculating kernel dependencies. I think this could be a problem because I think one of the issues is that the generic ide driver grabs control of the ide ports before the via driver, so I don't have access to control those ports and enable DMA afterwards. This could be completely wrong as I am not familiar with Linux details but regardless this is one issue that I would really want to get fixed.

The second thing is that before I had the driver for my old board built right into the kernel, and everything worked flawlessly back then. If I build the new VIA drivers into a new kernel, would that work?

As always I'm opened to any ideas that anyone may have, and would really appreciate some feedback on the points I raised, thanks!

Well I would definately try compiling your chipset support into the kernel as you suggested (got to be worth a try !).

Regards

Shmonkey

Yeah, I'll try to compile the VIA chipset driver into the kernel if nothing else works. Ideally I'd like to get my modules working properly though. Any ideas as to why I get the

No modules loaded - Kernel modules not enabled

during boot? How can I build a kernel with modules such that it works properly?

Strange thing is that once it boots up I can still 'modprobe' or 'insmod' modules.

Umm... IIRC, it's a bad idea to have hard-drive related things complied as modules. If they're not built into the kernel, they get loaded later in the boot process, when they have to be read from the disc.

If the kernel needs a module to know how to talk to your hard drive, and the module is located on the hard drive, you're going to have trouble!

Besides, why would you want something compiled as a module if you know you're always going to need it?

Yeah, I know what you guys are saying. I agree that compiling the chipset in would be a good idea, and probably solve my DMA issues. But I would still like to get my other kernel modules working properly. The kernel doesn't detect any of my modules and hence doesn't install any during boot time. I have to 'insmod' everything on my own after logging in. This has goods and bads but I really wanna fix this issue before I run into other problems further down the road.

Anyone have any ideas? And how do I setup modprobe properly with kernel 2.6.7?

Have you added the modules you want to start on boot to the /etc/modules.autoload.d/kernel-2.6 file?

Incidentally, I've just recently switched to Gentoo, so I'm in the process of getting everything set up. I was dissapointed at how slow everything was going. And it refused to allow me to turn on DMA - same problem as you've got.

So last night, I recompiled the kernel properly, with the NVIDIA IDE driver enabled and every other IDE driver switched off. Then rebooted.

DMA is now enabled, and executables that were taking 12 seconds to load now only need 3. Not bad, eh? :)