Kernel parameters
Some aspects of the Linux kernels behaviour are controllable via so called kernel parameters. These are parameters similar to the ones that you would provide for a command like $ ls or $ cp in a shell, only that they are appended to the kernel/image line in your bootmanagers config file (for lilo this would typically be /etc/lilo.conf, for grub it would be /boot/grub/menu.lst).
An example line from grub could look like this:
kernel /lfskernel-2.6.9 root=/dev/hda6 rw idebus=66 vga=791 splash=silent acpi_sleep=s3_bios
For a complete overview of all available parameters see /lib/modules/`uname -r`/source/Documentation/kernel-parameters.txt.
Typical parameters used on ThinkPads
The following table gives an overview of the kernel parameters typically needed on ThinkPads.
| parameter | description |
|---|---|
acpi=off |
disables ACPI (keeps it from overriding APM) |
acpi_sleep=s3_bios |
makes the system call the video BIOS to reenable video on resume from suspend-to-ram (use this if you experience a blank display after resume while your system seems elsewise awake) |
hda=noprobe |
Sometimes needed for DMA support for system hard disk on recent models (see Problems with SATA and Linux) |
hdc=noprobelibata.atapi_enabled=1 |
Sometimes needed for DMA support for the optical drive on recent models (see Problems with SATA and Linux) |
idebus=66 |
set IDE bus speed to 66 MHz (66 is maximum supported) |
nolapic |
tells the kernel not to use the local APIC (use if you have problems with ACPI) |
lapic |
tells the kernel to use the local APIC, even when it is disabled by the BIOS (older models like a T42 or R51 don't have this option in the BIOS and don't enable the local APIC) |
noresumenoresume2 |
boots without resuming after a suspend-to-disk (for swsusp and suspend2, respectively) |
resume=/dev/hdaXresume2=/dev/hdaX |
tells the kernel where to find the suspend-to-disk image to resume from (for swsusp and suspend2, respectively) |
root=/dev/hdaX |
tells the kernel where to find the root filesystem |
speedstep_coppermine=??? |
supposed to tell the kernel that you have a speedstep capable coppermine processor, but could possibly not work anymore with newer kernels |
forcepae |
tells the kernel that the CPU supports Physical Address Extension (PAE), even if it is not the list of supported CPU flags (see Pentium M Dothan) |
The following table gives an overview of the kernel parameters typically needed on ThinkPads.
| parameter | description |
|---|---|
vga=835 |
for 1400x1050 framebuffer resolution |
vga=0x33c |
same as above |
video=vesa:ywrap,mtrr |
enables mtrr and .... |
video=radeonfb:vesa:1400x1050-32@60 |
for using accelerated radeonfb framebuffer |
