could use help debugging black screen on RS780 (xf86-video-ati-6.13.0, radeon)

[Larry Doolittle]

On Fri, Jun 04, 2010 at 06:09:43AM -0700, Larry Doolittle wrote:
> The motherboard is a Biostar TA790GX XE, conveniently listed
> at Newegg as item N82E16813138140.  The monitor (LCD panel)
> worked recently at 2048x1152 driven with a 10-year-old Matrox
> and the same VGA cable.  It's a Samsung model 2343BWX.
> 
> I have started downloading the files to install the i686 version
> of Debian Squeeze, instead of the amd64 version, just in case
> I have run into a word-length bug.  I should have a chance to
> try that this weekend.

It was a long and winding path, but I think there's a short
answer:  someone disabled the traditional herringbone start
pattern for the X server, so all my tests just starting X
(no clients) gave a black screen -- not even the stylized
"X" cursor I have known for literally 17 years.  How am I
supposed to know the server is running?

When I finally ssh in and "DISPLAY=:0 xclock -geom +100+100",
I see the server works fine.  Install a few clients, and the
system works fine!  Well, still some rough edges, but I'll
have to deal with those another day.  Unless someone can
explain why X no longer starts with a herringbone, or show
how to re-enable it, I consider this thread closed.

Sorry for the noise -- trust me, I went through many hours of
effort before discovering the (lack of) problem.

   - Larry