[LinuxBIOS] Geode GX1 and IRQ tables

Ronald G Minnich rminnich at lanl.gov
Sun Dec 4 05:42:47 CET 2005

Richard Smith wrote:
>>The next problem is that in spite of this, the ethernet chip doesn't
>>generate interrupts anymore.
>>Is there any additional configuration /setup that I need to do?
> I had the exact problem with the 440BX.
> Is the IRQ actually routed correctly?
> On many bridges Linux expects the BIOS to have properly set up the IRQ
> routing from the PIRQ to the IRQ.  Just having the table correct may
> not be enough.   On the 440BX I had to do it manually.  Boot COTS and
> compare the lspci -xxx of your northbridge with that of linuxBIOS and
> then go look for differences in the PIRQ to IRQ n routes.

in many cases, the fuctory BIOS IRQ table is wrong, requiring you to fix 
it up by hand. This is very common.

Also, if you have the old GX southbridge, linux is wrong: since 1/2 the 
GX1 bioses seem to set up the irq table wrong, linux does a Bad Thing in 
the cs5330 (or whatever it is) driver. See the delta on this driver from 
2.4.18 to 2.4.19. It's a huge mess.

best bet is just forget the irq table and put the right IRQ value in the 
chip directly.


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