Bug#891731: nvidia-legacy-check: check fails preventing apt full-upgrade

[John Kozak]

Package: nvidia-legacy-check
Severity: serious

Dear Maintainer,

Attempting to do `apt full-upgrade` fails with a message with banner
"Configuring nvidia-legacy-check" and this body:

 | This system has a graphics card which is no longer handled by the NVIDIA driver (package nvidia-driver). You   │
 │ may wish to keep the package installed - for instance to drive some other card - but the card with the         │
 │ following chipset won't be usable:                                                                             │
 │                                                                                                                │
 │ 05:00.0 VGA compatible controller [0300]: NVIDIA Corporation G98 [GeForce 8400 GS Rev. 2] [10de:06e4] (rev     │
 │ a1); 06:00.0 VGA compatible controller [0300]: NVIDIA Corporation GT200b [GeForce GTX 285] [10de:05e3] (rev    │
 │ a1)                                                                                                            │
 │                                                                                                                │
 │ The above card requires either the non-free legacy NVIDIA driver (package nvidia-legacy-340xx-driver) or the   │
 │ free Nouveau driver (package xserver-xorg-video-nouveau).                                                      │
 │                                                                                                                │
 │ Use the update-glx command to switch between different installed drivers.                                      │
 │                                                                                                                │
 │ Before the Nouveau driver can be used you must remove NVIDIA configuration from xorg.conf (and xorg.conf.d/).  │
 │                                                                                                                │
 │ Install NVIDIA driver despite unsupported graphics card?

I am already using `nvidia-legacy-340xx-driver` for the two graphics cards
on this system and `nvidia-driver` is not installed.

console messages after clicking "no" are:

  *** The following unsupported devices are present in the machine:               
  05:00.0 VGA compatible controller [0300]: NVIDIA Corporation G98 [GeForce 8400 GS Rev. 2] [10de:06e4] (rev a1)
  06:00.0 VGA compatible controller [0300]: NVIDIA Corporation GT200b [GeForce GTX 285] [10de:05e3] (rev a1)
  Aborting nvidia driver installation.
  dpkg: error processing archive /var/cache/apt/archives/nvidia-legacy-check_384.111-4_amd64.deb (--unpack):
   new nvidia-legacy-check package pre-installation script subprocess returned error exit status 1
  Errors were encountered while processing:
   /var/cache/apt/archives/nvidia-legacy-check_384.111-4_amd64.deb
  E: Sub-process /usr/bin/dpkg returned an error code (1)

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.14.0-3-amd64 (SMP w/16 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled