Poor PCMCIA performance

["Gary Hennigan" <glhenni@sandia.gov>]

I have an IBM Thinkpad 600E and a Linksys Etherfast PCMCIA 10/100 -
56k combo card. I've had the card about a year but have never really
had occasion to worry about performance, until now. I started
transferring a CD image over to it and the performance was absolutely
abysmal. We're talkin' about 120kB/s. At that rate it would've taken
about 1.5 hours to transfer the CD image.

I had an old 10Mb 3Com card sitting around and I thought I'd try it. I
pop out the Linksys, pop in the 3Com and voila. At *LEAST* 600kB/s.

That prompted some further investigation. The laptop dual boots so I
booted Win2k with the Linksys card and lo and behold I get 1,112kB/s
with the Linksys under Win2k!?!? 

Another data point, the modem part of the Linksys card doesn't
function under Linux. It works fine under Win2k. The modem on the 3Com
card works fine under Linux.

Looking at the output of "cardctl config" for the 3Com and Linksys
yields:

3Com:
Socket 0:
  Vcc 5.0V  Vpp1 0.0V  Vpp2 0.0V
  interface type is "memory and I/O"
  irq 3 [exclusive] [level]
  function 0:
    config base 0x0800
      option 0x47 status 0x00
    io 0x0300-0x030f [16bit]
  function 1:
    config base 0x0900
      option 0x67 status 0x08
    io 0x03e8-0x03ef [8bit]

Linksys:
Socket 0:
  Vcc 5.0V  Vpp1 0.0V  Vpp2 0.0V
  interface type is "memory and I/O"
  irq 3 [shared] [level]
  Speaker output is enabled
  function 0:
    config base 0xffe0
      option 0x43 status 0x08 pin 0x00
    io 0x0300-0x031f [auto]
    io 0x0af8-0x0aff [8bit]

The only hint I get from this is that the linksys is sharing IRQ3, but
according to /proc/interrupts it's the only thing using IRQ3:

3:	4618    XT-PIC pcnet_cs

So I don't know if it's just sharing it between the Enet and Modem
part of the card or what?

Any help would be appreciated. I'm stumped!!

Gary