Created attachment 138046 [details]
dmesg with drm.debug=14
Radiant Systems P845 has no LVDS (only a VGA port) but BIOS keeps LVDS enabled.
/sys/kernel/debug/dri/0/i915_vbt is empty.
Isn't this a BIOS issue?
It probably is - but nobody will fix it. The machine is old, there's no support. And it works in Windows.
That's why I wrote the patch (see the URL).
First of all. Sorry about spam.
This is mass update for our bugs.
Sorry if you feel this annoying but with this trying to understand if bug still valid or not.
If bug investigation still in progress, please ignore this and I apologize!
If you think this is not anymore valid, please comment to the bug that can be closed.
If you haven't tested with our latest pre-upstream tree(drm-tip), can you do that also to see if issue is valid there still and if you cannot see issue there, please comment to the bug.
VBT is there...
Maybe you don't have the debugfs configured and mounted?
[ 6.084841] [drm:intel_bios_init] VBT signature "$VBT MONTARA-GM ", BDB version 114
But yeap, something odd with the VBT there:
[ 6.084883] [drm:intel_opregion_get_panel_type] Failed to get panel details from OpRegion (-19)
What is strangest is that LVDS detection not only comes from VBT, but also is detected as connected later.
Anyways, what is the issue itself?
I see that VGA is also detected and connected.
Is it a blank screen kind of issue? Is it a regression?
Did you try to manually force mode changes from userspace?
(In reply to Rodrigo Vivi from comment #4)
> VBT is there...
> Maybe you don't have the debugfs configured and mounted?
> [ 6.084841] [drm:intel_bios_init] VBT signature "$VBT MONTARA-GM ",
> BDB version 114
Old platforms don't have opregion, so our debugfs based VBT dumper doesn't work. One needs to use intel_bios_dumper from intel-gpu-tools. We should probably fix the debugfs code to dtrt on these platforms as well...
> But yeap, something odd with the VBT there:
> [ 6.084883] [drm:intel_opregion_get_panel_type] Failed to get panel
> details from OpRegion (-19)
> What is strangest is that LVDS detection not only comes from VBT, but also
> is detected as connected later.
The lack of opregion explains that too I believe. Although the logic is quite convoluted so you have to read the code rather carefully to see it.
Related to  where I asked for the bug to be filed.
Based on the clues in the dmesg, the VBT seems interesting.
Ondrej, could you attach the intel_bios_dumper result please? The tool is available in the intel-gpu-tools package https://cgit.freedesktop.org/drm/igt-gpu-tools/
Created attachment 139076 [details]
Jani, does this info provide clues?
Please try . Based on the VBT I think this should work, without quirks.
Reporter, can you test patch mentioned by Jani.
The patch is incorrect: https://www.spinics.net/lists/intel-gfx/msg165434.html
DMI quirk merged so marking as fixed.
Author: Ondrej Zary <firstname.lastname@example.org>
Date: Fri Mar 9 23:22:04 2018 +0100
drm/i915: Disable LVDS on Radiant P845
Ondrej, are you able to verify?
I confirm that the bug is fixed in kernel 4.17.