Bug#996000: general: System does not boot with second monitor attached

[Asbjørn Sæbø]

Package: general
Severity: important
X-Debbugs-Cc: ***@live.com

Dear Maintainer,

I installed Debian 11 on a new computer (with a single monitor during installation, connected with HDMI).

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).

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".

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).


I would expect the system to boot also with two monitors attached.

[Andrew M.A. Cater]

Post by Asbjørn Sæbø
Package: general
Severity: important
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.

Post by Asbjørn Sæbø
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.

Post by Asbjørn Sæbø
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?

Post by Asbjørn Sæbø
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

Post by Asbjørn Sæbø
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

[Andy Simpkins]

Control: Severity -1 normal

Post by Asbjørn Sæbø
Package: general
Severity: important
Dear Maintainer,
I installed Debian 11 on a new computer (with a single monitor during installation, connected with HDMI).
Installation went well, but the monitor came up with a very limited resolution (1024x768, I think).

That isn't surprising, the installer (DI) will try and use only a minimum set of possible configurations, in order to function with most hardware it encounters

Post by Asbjørn Sæbø
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).

Ack that sounds about right to me too: AFAICT Rocket Lake, UHD 750 is not yet officially supported in the linux kernel; i915 series has a generic driver, but not with full support for all devices in the series
this is perhaps a bit too new, and you may have to wait a while for the kernel drivers to arrive. [0]

Post by Asbjørn Sæbø
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".

This is stating that that you haven't enabled 'Intel virtualization technology' - this should have no effect on the graphic driver support, you would need to enable this if you want to run Virtual Machines.

Post by Asbjørn Sæbø
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).
I would expect the system to boot also with two monitors attached.

I would expect this as well - but until there is official support in the kernel for your new hardware then I am afraid that you may have to put up with only connecting the monitor after boot.

Trying newer, back ported kernels, when they become available, is probably your best bet. You could try watching the kernel.org releases looking specifically for the mentions of i915, Rocket Lake, or UHD 750 beforue you try [1]


Very best wishes, and good luck with trying new kernels when they arrive

/Andy
(RattusRattus)

[0] https://gist.github.com/Postrediori/556706b28aff3b831d9e41acb47418c5
[1] https://www.kernel.org/

[Debian Bug Tracking System]

Post by Andy Simpkins
Severity -1 normal

Bug #996000 [general] general: System does not boot with second monitor attached
Severity set to 'normal' from 'important'

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