New technologies are fine, but sometimes they just give headaches. The harddisk found in the T43p is one such case. It's connected to a SATA controller via a so called SATA-to-PATA bridge, and the problem is that powermanagement and suspend-to-RAM is not working with stock kernels from kernel.org, at least not with the currently latest version 2.6.14.

But, after reading and re-reading the page about the topic in the ThinkWiki, playing around with different combinations of patches and following bits of the discussion in the LKML and linux-ide archives, at last I got the whole thing working. But of course this is rather unsafe territory and I give no warranty whatsoever that it works for you or that there will be no loss of data, so continue at your own risk.

Used Patches

Kernel 2.6.14:

• from this LKML posting I got the suspend-to-RAM patch, and even though there seems to be a competing implementation this one "works for me". Use the "Get diff 1" link in the menu on the left to get the patch in proper text-only format.
• from http://rtr.ca/dell_i9300/kernel/kernel-2.6.13/ I downloaded 02_libata_passthru.patch and 03_libata_passthru_bugfix.patch so I can use hdparm and the smartmontools needed for setting powersaving parameters among other things. 02_libata_passthru.patch does not apply cleanly since a couple of things are already in the suspend-to-RAM patch from above, so I updated it and it's attached below.

In the root directory of the kernel source, apply the patches in the following order:

patch -p1 < /path/to/downloaded/suspend-to-ram-from-lkml.patch
patch -p1 < /path/to/downloaded/02_libata_passthru.fixed.patch
patch -p1 < /path/to/downloaded/03_libata_passthru_bugfix.patch

Kernel 2.6.15:

• the libata_passthru has been included into the vanilla kernel, so only the suspend/resume-patch is still necessary, an up-to-date version for 2.6.15-rc6 and also the 2.6.15 final can be found at http://tpctl.sourceforge.net/tmp/sata_pm.2.6.15-rc6.patch.

Kernl 2.6.16:

• no more patches are needed, both a self-compiled kernel and the current kernel package in Debian unstable (linux-image-2.6.16-1-686) have no problems regarding the harddisk.

If necessary, recompile and install the kernel as shown in the kernel configuration page.

After booting into the new kernel, commands like

hdparm -I /dev/sda

to show information about the drive or

hdparm -y /dev/sda

to spin down the harddisk should work. (the -i option does not, interestingly enough)

Once that works it's time to configure suspend-to-RAM or start using the Laptop Mode Tools.