Bug#996000: general: System does not boot with second monitor attached
On Sat, Oct 09, 2021 at 09:18:06PM +0200, Asbjørn Sæbø wrote:
> Package: general
> Severity: important
> X-Debbugs-Cc: gaffe_1@live.com
>
> Dear Maintainer,
>
> I installed Debian 11 on a new computer (with a single monitor during installation, connected with HDMI).
>
What make/model of computer? A server or desktop?
If you can run lspci or dmesg and quote the line that show the actual
device for video that would help enormously.
> Installation went well, but the monitor came up with a very limited resolution (1024x768, I think).
> After a bit of googling, I found that the drivers for the Intel graphics on this board (Rocket Lake, UHD 750) were not
> included in the 5.10 kernel that came with Debian Bullseye. I installed kernel 5.14 from Debian Testing, and that seemed to
> solve the issue - I got full resolution (still with a single monitor attached).
Not a good idea to do this: mixing releases may cause problems that are hard
to debug and hard to solve. If you can afford to reinstall with just Debian
11, do so. It is likely that your computer needs firmware: this is from
the non-free archive so is not included by default.
It would be a good idea to use the unofficial image which includes non-free
firmware to test this. The non-free firmware is in non-free because we often
do not have source / cannot modify the files we distribute - but it is
prepared by Debian developers.
>
> Taking the system into use as my main system, I set it up with two monitors, one connected with an HDMI cable, one with a
> DVI cable. (Both monitors are Benq 24 inch 1920x1080.)
> Booting the system, it hangs during boot, with a message "VMC (outside TXT) disabled by bios".
>
How did you install this system initially - via UEFI or in Legacy BIOS mode?
> Booting the system with only the HDMI-connected monitor attached works as expected, the system completes the boot sequence,
> I can log in and use the system.
>
> Attaching the second monitor after boot also works, both monitors are recognized and works.
>
> As a workaround, I tried enabling "Intel virtualization technology" in the BIOS. Booting with both monitors attached, there
> is no longer any error message, but the system still hangs during boot (with a blank screen).
>
This is diagnostic of missing firmware. You probably need
firmware-linux-nonfree and firmware-misc-nonfree. It might be easiest to
install with just the firmware image.
If not, add contrib and non-free to the stanzas in /etc/apt/sources.list
as in
deb http://deb.debian.org/debian bullseye main contrib non-free
deb-src http://deb.debian.org/debian bullseye main contrib non-free
deb http://deb.debian.org/debian-security/ bullseye-security main contrib non-free
deb-src http://deb.debian.org/debian-security/ bullseye-security main contrib non-free
deb http://deb.debian.org/debian bullseye-updates main contrib non-free
deb-src http://deb.debian.org/debian bullseye-updates main contrib non-free
then update, upgrade and install at least firmware-linux-nonfree
and firmware-misc-nonfree
>
> I would expect the system to boot also with two monitors attached.
>
This depends very much how the monitors are detected.
All the very best, as ever,
Andy Cater
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