Re: [2/6] 2.6.21-rc2: known regressions

Linus Torvalds
2007-03-09T18:07:11Z

On Fri, 9 Mar 2007, Ingo Molnar wrote:
> > Some day we may have modesetting support in the kernel for some
> > graphics hw, right now it's pretty damn spotty.
>
> having no video is what i'd have expected - but getting a /hang/ is not
> what i'd have expected.

I debugged a case exactly like this (with the TRACE_RESUME() thing) back
last November on my laptop.

The problem is that radeonfb actually *tries* to re-initialize the
graphics chips, but because it doesn't know all the details, it does it
wrong, and hangs the whole chip.

I forget exactly where it happened, and it might well be different for
you. But this is exactly what TRACE_RESUME can be used to pinpoint if you
want to try to debug it.

Linus