Re: atyfb & lockups

[Knut Petersen <Knut_Petersen@t-online.de>]

>I have an old PowerBook Wallstreet I here with a Rage LT-G. I've been
>booting it from Open Firmware instead of MacOS lately (thus didn't give
>a chance to the MacOS driver to do it's own tweaking of the chip) and
>the machine has been reliably locking up on me. Solid lockups. I finally
>figured out that the lockups appear to be atyfb related and that booting
>with video=atyfb:noaccel fixes it.
>It seems that when it's lockup, the whole machine is down, that is it
>won't take interrupts to get to the xmon low level debugger nor
>anything, thus I suspect the PCI is locked up.
>  
>
Well, there are other possibilities.

When does the lockup occure?  Immediately when booting? Later? During 
start of 
xdm/kdm? Random?

>Are there any ideas of where to look for the source of the problem ?
>
>  
>

I would start to investigate the case by instrumenting and extending the 
fb_sync code.
Try to include code there that resets the chip and switches to the 
noaccel counterparts of the
accelerated functions when a timeout occures. That way you should have a 
chance to resume.
Is the timeout counter ok? Maybe you should decrease/increase it.   If 
switching to
the noaccel function works, include a register dump before resetting the 
chip, use show_trace()
etc for further debugging.

cu,
 knut


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