The A531 is a laptop made by ECS (Elite Group). It is a low cost laptop, using a Transmeta TM5800 CPU.
Manufacturer's website about these: http://www.ecs.com.tw/products/a531.htm.
The built in Ethernet network card uses a Realtek 8139C chip. The standard "8139too" support of the kernel works fine.
The kernel config parameter is called "CONFIG_8139TOO"
Since I use Ethernet, I didn't need to use the modem. Apparently it can only be used under linux with a closed-source driver.
Kernel options "CONFIG_USB_EHCI_HCD" and "CONFIG_USB_OHCI_HCD". The "lspci" command claimed that 3 of the 4 ports were USB1.1 OHCI ports, and 1 was a USB2.0 EHCI port.)
The graphics chipset is an SiS 315. From what I can determine, the "sis" driver in XFree86 version 4.2 (the version in Debian Testing) and version 4.3 does not support this chipset, so I used the "vesa" driver.
The laptop also had an Svideo out (eg for a TV), but I didn't try or test this.
The touchpad will work fine as a PS/2 mouse, but the 4 scroll buttons will not work (by default). (Obviously you need "CONFIG_INPUT_PS2" support in the kernel).
The card identifies itself as "ALi M5451", and apparently uses a CMedia "CMI 9739" chip.
Kernel 2.6 ALSA drivers have direct support for this card ("CONFIG_SND_ALI5451" Sound -> ALSA -> PCI Devices -> ALi PCI Audio M5451). If using OSS instead of the recommended ALSA, the driver to choose says "Trident 4DWave DX/NX, SiS 7018 or ALi 5451 PCI Audio Core".
As mentioned on the other pages linked to at the top of the page, the Mixer volume was ignored, other than complete muting.
The card (and the ALSA drivers) support hardware mixing of multiple audio streams, so I didn't need to fiddle around with setting up software mixing for apps.
as well as the generic "-dev" and "bit-banging algorithms" I2C stuff required for lm-sensors.