Created attachment 99106 [details]
debug dmesg

My investigation of this led to mode being null. I guess I would have expected bios->fp_no_ddc to be set, but it wasn't. Will look at the attached vbios.

A workaround for now would be to change

drivers/gpu/drm/nouveau/nouveau_connector.c:nouveau_connector_detect_depth

        /* LVDS: panel straps */
        if (bios->fp_no_ddc) {
                if (bios->fp.if_is_24bit)
                        connector->display_info.bpc = 8;
                return;
        }

to be

        /* LVDS: panel straps */
        if (1 || bios->fp_no_ddc) {
                if (bios->fp.if_is_24bit)
                        connector->display_info.bpc = 8;
                return;
        }

Which will force it down this path. Alternatively you could change

                duallink = mode->clock >= bios->fp.duallink_transition_clk;

to be

                duallink = mode && mode->clock >= bios->fp.duallink_transition_clk;

Which would also avoid the crash.

DCB table at 0xd537 version 1.5
DCB 0: type 0 [ANALOG] I2C 0 heads 0 conntag 0 LOCAL OR 0 maxfreq 350000kHz
DCB 1: type 4 [???] I2C 1 heads 1 unk00_4 1 conntag 1 LOCAL OR 1
DCB 2: type 1 [TV] I2C 1 heads 0 unk00_4 1 conntag 2 EXT 0 OR 0

Well that's a little odd... I suspect that throws off some of the logic. Type 4 is "reserved". Yet, somehow it still detects that there's a LVDS...

nvbios doesn't print the other stuff, so it'll take some more decoding to work out what's what... might look at that later.

Created attachment 99115 [details]
dmesg after first patch (it's a different userland than first log)

Created attachment 99116 [details] [review]
patch #1

Created attachment 99117 [details]
X.org log with patch #1 applied

Created attachment 99122 [details]
X.org log with patch #1 applied and xf86-video-nouveau

Can you confirm that things work fine with the hack I suggested (i.e. your patch #1)?

(In reply to comment #8)
> Can you confirm that things work fine with the hack I suggested (i.e. your
> patch #1)?

No, it didn't work. Nouveau does not crash anymore, but the screen just flashes and shows black and white garbage.

Sadly I do not have access to the hardware anymore, it was a customer's hardware and he took it away. I suppose you can close this bug.
Sorry for not closing this down before, and thanks a lot for your help and time.

-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/xorg/driver/xf86-video-nouveau/issues/108.