How to Debug Linux Kernel Boot process
 

Hi,

I am trying to enable DMA modes for my Hard drives by compiling the 'AMD and Nvidia IDE Chipset' option under Device Drivers->ATA/ATAPI/MFM/RLL support in 'make xconfig'. Now when I boot my system with drivers built into the kernel nothing happens. The system boots normally but the hard drivers does not dectect the drivers required for DMA support. So is there a way where I can see why it is not able to load/detect those drivers by enabling some kind of debugging during the Linux Kernel boot process?

I am using Debian etch with kernel 2.6.16.

Thanks

In the 2.4 kernel there was an option you had to set in xconfig if you wanted DMA to be automatically selected by the kernel at boot time. This is true independent of what hardware/modules you are using. Otherwise an init script had to handle it. I am guessing that this is true for 2.6 also.

If you compiled these as modules (rather than directly into the kernel), you can see if those modules have been loaded using the command lsmod.

There are probably some boot time messages in /var/log/messages or other log files in /var/log.

I have already done what you have suggested and I am struggling for the last 1 week to get it work. When I do the lsmod I can see the module loaded but still it seems that my IDE drive is not aware of it. That's why I would like to debug the instance "When the module gets loaded" during the boot time. What is the most efficient and accurate way to do that?

Thanks once again for replying.

Have you looked at this thread (particularly post #8)?

http://www.linuxquestions.org/questi...d.php?t=298024

Yes dude I have already done loads of researching on the Internet and I think it a BIOS issue so I would first like to debug the module and see what values do it hold when the Kernel tries to load it.

Thanks once again.