has the i915 "black screen" boot issue returned? [BISECTED]

[Robert P. J. Day]

On Fri, 28 Jan 2011, Chris Wilson wrote:

> We're starting to get into ACPI backlight breakage territory... We
> have identified that the regression was much earlier, just masked by
> other breakage.

  as additional info, i went through this for a while during the
2.6.37-rc* progression.  it came, it went, it came back again.  then
everything was fine with both 2.6.38-rc1 and 2.6.38-rc2, and then
this.  this is on a gateway NV79 laptop running a fully-updated ubuntu
10.10.

> Let's clarify the symptoms: black panel, no backlight, no output at
> all (not even at shallow angles), but the machine is alive?

  exactly, same as it's always been when things fail.  that the
machine is still booting is obvious from lots of disk activity,
culminating in the little ubuntu drum roll at the login screen.  and,
as i mentioned before, i do get a couple early kernel messages
(/dev/pts, ureadahead), and that's where it goes black.  for a *good*
boot, what i would see at that point is the font size getting much
smaller and the boot continuing.

> Can you remotely access the machine and grab debug logs from when it
> is broken?

  i'd love to, but can't at the moment.  i'll see if i can scare up a
second machine later and try it.  if i can, what *precisely* would you
like me to post?  i'm guessing dmesg, Xorg.0.log, that sort of thing.

> >   so, before i launch into this, is there anything else i might
> > report about my system and its current setup that someone might
> > want to know?
>
> We're now just looking for telltale signs of an error.

  all right.  and since we're beyond git bisection, can you post a
list of say 2 or 3 tests you want me to try in order?  as you're the
expert here, it would make more sense for you to try to optimize the
search pattern here.

rday

-- 

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Robert P. J. Day                               Waterloo, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
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