OK, so I did my research and now I can load my Ethernet drivers at eth0 (see
thread: "Other Ethernet cards - modules"). Another area where Linux beats
not just NT, but also older "Unixes I Have Known".
Now, I have a problem on one PC which I thought would be easy to fix, but
it's proving tougher than I imagined.
This PC has
- a Digital DE435 Ethernet board (PCI)
- an NCR53C800 SCSI card (also PCI)
According to the BIOS, both of these are assigned IRQ 12 to share. This
works fine in all Linux configurations I have tried up to now. My normal
setup is Debian 2.1 with kernel 2.0.36.
With tomsrtbt 1.7.118, I can't get the SCSI module to load (with insmod).
It can't assign IRQ 12 ("request IRQ 12 failure").
Aha, I thought, this must be due to the Tulip driver. The Tulip (21040)
driver is a generic driver which loads on most cards derived from the 21040
chip, but there are also specific drivers for certain Tulip-based cards.
For example, on my DE435, it's de4x5.o.
So, I replaced Tom's kernel (on my tomsrtbt disk) with my usual 2.0.36
kernel, which has no Tulip driver, and it works. Then, to make sure, I
added the Tulip driver to my tomsrtbt kernel, and the problem came back.
QED, I thought. Except...
When I boot my kernel with the Tulip driver as part of my normal Debian
Linux setup, there is no conflict. I see the Tulip driver (this isn't
normally what I'd use, of course), then I can log on and load the ncr53c8xx
module. Similarly if I boot Tom's 2.0.36 kernel on my Debian setup - no
problem.
I then built a kernel with the DE435 driver instead of the Tulip. Same
result - with tomrstbt, I get the conflict, and with Debian, it's OK.
So, it appears that the problem is something to do with IRQ sharing, which
works with my Debian setup but not tomsrtbt. But it's not in the kernel (or
at least, not exclusively) because the same kernel does or doesn't have the
problem, depending on "other stuff". What could it be ?
About the only clue I can think of (POTENTIAL RED HERRING ALERT) is that on
Debian, rc.S runs isapnp. This shouldn't be relevant (on my system it just
finds my ISA PnP Winmodem ;-) ), but it does produce the intriguing message
"lspci not found, so PCI conflicts not checked". (Of course, that doesn't
sound like it's fixed PCI IRQ sharing, but I'm grasping at straws.)
By the way, if there's a vote for modules to be in the tomsrtbt kernel, I'd
suggest taking the Tulip driver out, because of its tendency to load itself
on cards where another driver might be more appropriate.
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|\ | o _ |/ Life's like a jigsaw
| \| | |_ |\ You get the straight bits
But there's something missing in the middle
Nick Brown, Strasbourg, France (Nick(dot)Brown(at)coe(dot)fr)
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