Re: atyfb & lockups

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

> Well, there are other possibilities.
> 
> When does the lockup occure?  Immediately when booting? Later? During 
> start of 
> xdm/kdm? Random?

During boot, when drawing text in console mode, usually when it starts
scrolling but not necessarily.

> 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.

Yah, I should do something like that. I remember trying to track that
bug down a while ago now, and I think I had it working by adding syncs
all over the place.

However, I think the problem is more likely to be some bad fifo or
bandwidth setting in the engine causing it to lockup when loaded. It
works if I boot MacOS and use BootX to then boot linux, though I then
have different display problems (definitely look like incorrect settings
of the display fifo).

> 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.

Will do all of these as soon as I find some time. My initial post was
mostly to ping in case it was a known issue or somebody else already
tracked it down.

Ben.




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