[LinuxBIOS] [PATCH] Intel 82371EB: IDE init support (or: S1846 boots Linux kernel)

Corey Osgood corey_osgood at verizon.net
Tue May 29 08:42:36 CEST 2007


Uwe Hermann wrote:
> Here's a patch which adds IDE support to the Intel 82371EB southbridge.
> 
> With this patch I can boot a Linux kernel with FILO up until the login
> prompt. I can login and use the system, too. Feels a bit slowish, but
> maybe that's just because the CPU and disk are dead slow...

And perhaps also because you're using a serial console (on said dead
slow system)? Still, great work!

> (Hm, there's an "Enable Ultra DMA/33" setting on the IDE controller --
> should I enable that in the southbridge code, or can Linux do that and
> it's superfluous in the BIOS?)

Couldn't hurt to enable it (except for a couple extra microseconds spent
in the BIOS). Although probably best to have it as a config option. Not
that I expect anyone to have any non-dma disks, but some compact flash
adapters don't like dma mode, although they tell the BIOS/linux that
they support it. On my little file server, debian takes about 3 minutes
to boot because it tries every DMA mode before it gives up and disables
it. But I can't disable dma outright, because the two hard drives do
support it, and I don't want them to be deathly slow.

> Anyway, this patch also fixes random other southbridge files, and I'm
> adding my copyright header to some other files as they're either
> trivial and/or my changes are pretty much a rewrite...
> 
> There's some more stuff missing from the 82371EB (e.g. USB support),
> but that's for another patch...

Hmm...from the code I've seen for other southbridges, namely vt8235 and
i82801ca/db/dbm, most seem to have code for enabling the USB, and then
have it commented out, presumably because the developer(s) discovered
that it worked fine with whatever normal pci device init linuxbios does.
Does linux automagically load the usb modules?

-Corey




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