[Intel-gfx] i915: Dell E6410 Ironlake display detection

[Ben Guthro]

I posted a similar question to LKML yesterday, but perhaps this is a
better forum for this discussion, as it seemed to get lost amongst
many other non-graphics related discussions.

I have a problematic machine, that I have traced the problem down to
what I think is an issue with the i915 detection of the LVDS on the
Ironlake chip.

The machine in question is a Dell Latitude E6410 - i5 laptop, with the
intel Ironlake chip, and the failure condition is such that when the
boot sequence switches into KMS mode, the screen
goes black, and never comes back.

It seems to be very similar to both
https://bugs.freedesktop.org/show_bug.cgi?id=28224
and
https://bugs.freedesktop.org/show_bug.cgi?id=28070

However, I have tried all of the patches suggested on these bugs, to
no avail (yet)

My base install is Ubuntu 10.04, and I've spun through a few kernels
to try to bisect the problem. Unfortunately, I've been unable to find
a kernel that works, but I have settled on linus' 2.6.35rc3 for
debugging this...

I can get the machine to come up on an external display, if switched
at the BIOS screen...but /sys/class/card0 never shows an LVDS...and
dmesg doesn't seem to be throwing any errors.

If you have any thoughts on what I might try next, in attempting to
debug this issue, I'd appreciate any pointers, as the intel cards
isn't my particular area of expertise, but am capable enough to read
the code...


Regards,

Ben