[LinuxBIOS] RE : Re: VGA bios and i/o access for powerpc

[jf simon]

Ronald G Minnich wrote:

>
> keep in mind that, if it works on one *instance* of a card from vendor 
> X, it may fail on the same model card from vendor X, purchased on the 
> same day, from the same store, on the same shelf.
>
> PC hardware is wonderful.
>
Thanks. I will run  a trace and see first how large it is (100's or 
1000's of cycles). Maybe there are pci cycles that are checking  from 
flags to be set on the vga chipset, and these could explain the behavior 
differences you are mentionning, in case the flags hasn't changed to the 
expected value before the init process goes on. Or timings between 
cycles that need to be respected. I think I can write some perl script 
that will extract these  informations from the analyser trace and 
produce the right C code. I hope the pci graphic card doesn't rise 
interrupts during that process though..
-jfs


	

	
		
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