This is my attempt to bring civility to the world of this poor, misguided Dell Latitude XPi P75T laptop. Along with being forced to run an inferior operating system, this pitiful creature was a beast of burden at a... business school (GASP!).
Thanks to the Linux on Laptops site, I was able to find other references, which included old information about an XPi P90T as well as an XPi P90D and the Advanced Port Replicator (not the one I have, but still useful information). I also found related information for configuring X at XFree86 Cirrus Logic Laptop Configurations and configuring APM at MobiliX - Mobile Computers and UniX. Finally, I found one last page dealing specifically with installing on a P75T, but the information is dated and incomplete.
The Dell website has surprisingly little technical information about this model. What information I did find was only through a Google search, and not through navigating the Dell support site. Specific information can now be found about the Dell™ Latitude™ XPi, the Dell™ Advanced Port Replicator — Ethernet III for Latitude™ LXP 4 D/T, XP4, XPi, and XPi CD Computers and the Dell™ DeskDock for Latitude™ Notebook Systems.
First, I'll translate some of the hardware specifics for you. On the laptop itself, the only hardware that is hard to figure out is the LCD and VGA chip. To start off, the model number can usually be found on the bottom of the laptop or listed in the BIOS. For example:
P90ST ^^^^^ |||++---- D = DSTN (640x480 super-twist) ||| T = TFT (640x480 active-matrix) ||| ST = SVGA TFT (800x600 active-matrix) |++------ CPU Speed in MHz Pentium
The machine I have is a P75T, meaning it is a Pentium (the original; no bloody II, III or 4) at 75 MHz with a 640 x 480 TFT screen. According to the Dell website, only Latitude XPi laptops that run at 75, 90 or 120 MHz (which excludes the XPi P100SD, XPi P133ST and any XPi CD model) use the Cirrus Logic CL-GD7543 chipset. A complete list of video modes can be found here. For my laptop, I hope to run 640x480 with at least 16-bit color.
Acquiring memory for this machine caused me a bit of confusion. The low-end XPi systems have 8 Mb soldered on, and Dell sold them in two default configurations (with and without a second 8 Mb SODIMM). All XPi systems have two SODIMM slots, and for most of these machines you can only have a maximum of 40 Mb (8 Mb plus 2 * 16 Mb SODIMMs). The one deviation is that the XPi CD w/Pentium MMX processors can use 32 Mb SODIMMs, so they do exist. But some sellers just say "For Latitude XPi" even though according to Dell they won't work in my laptop. If anyone wants to contest this, drop me a line. I'd love to run 72 Mb in this laptop, but I'm not willing to buy the memory just to find out.
The chipset is the Cirrus Logic/Pico Power "Golden Gate" (specifically the PT86C718), which is a Pentium offshoot of their "Redwood" chipset for 486's. While I haven't found out anything special about the hard drive or IDE chipset, I did learn the hard way that fiddling with hdparm can get you into big trouble if you aren't in single-user mode. The most efficient command I've found is:
hdparm -c0m16X00 /dev/hda
The 'c0' and 'X00' are redundant with a default Debian install. Other settings either make little difference in measured performance, or are not allowed by the drive (such as '-c3d1').
Something else to note is that this system doesn't have a PCI bus, unlike more modern laptops. For the PCMCIA (PC Card) slots, this means that CardBus cards are unsupported. I am not sure if they will even work at all. Again, if you have experience to the contrary, then e-mail me. The video controller is listed as "local bus" on the Dell webpage, which to me implies VL-Bus (VESA Local Bus, primarily for video cards), but from my experience with a VL-Bus 486 there is no probing or activating involved. It's either there or it isn't, and the kernel doesn't really tell you much about it.
For the docking station, we have:
Chip set AIC 6360; SCSI-2 compliant Data bus width 16-bit ISA host bus interface Data transfer rate 10.0 MB/second I/O address 140h IRQ line IRQ11
Chip set 3Com® 3C913B; 10Base-T Ethernet Data bus width 16-bit ISA host bus interface I/O address 300h IRQ line IRQ10
Operating system of choice for this install was Debian 2.2r2 (Potato).