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Passing boot parameters

The exact details on how to append boot parameters should be checked in the x86 UEFI case, see section "The Boot Screen" of the installation manual, and use

to check what is working.

Braille

Starting from version 0.9.1-4, debian's qemu-kvm has support for a virtual braille device. That means that you can very easily (i.e. without any braille hardware) test the debian installer support for braille devices by just installing brltty-x11 (at least version 3.10~r3715-1) and running:

$ /sbin/brltty -b xw -x no -A auth=none,host=127.0.0.1:1
$ BRLAPI_HOST=127.0.0.1:1 kvm -usbdevice braille -cdrom mini.iso

The first command will show a window that displays what would be displayed on a braille device. If you have issues with it, add -l debug -n -e to the command line to get more debugging details. If it's complaining about the font, try to append -B font='-*-fixed-*-*-*-*-*-*-*-*-*-*-iso10646-1' or even -B font='-*-fixed-*-*-*-*-*-*-*-*-*-*-iso8859-1' .

The second command starts the installer (without harddisk so only the first few installation steps can be tested). If qemu/kvm complains that it doesn't find the "braille" backend, it was probably built without brlapi support. Make sure to have the libbrlapi devel package installed when building qemu/kvm. The isolinux boot menu does not show on the braille device. Just "blindly" hit enter.

After the installer has booted you should see:

Serial braille support

To test the serial device support, replace

with

and append

to the kernel command line.

braille hotplug support

To test hotplug support (new in wheezy with brltty 4.2-9), replace

with

to remove the braille device but keep the USB tree initialized by qemu/kvm, and after d-i startup, press ctrl-alt-2 to get into the qemu/kvm console, and there type

chardev-add braille,id=brl
device_add usb-braille,chardev=brl

or more simply, with old versions of qemu/kvm:

and use ctrl-alt-1 to switch back to the installer. Debconf should get killed and restart in text mode.

After installation

On reboot into the newly-installed system, nothing more should be needed to get braille output again. This should work when installing without a network mirror too. If the (gnome) graphical desktop task was chosen, orca should get started to read gdm's chooser, and sound effects should be enabled. The user created during d-i should get orca and sound effects enabled in its session too.

Low vision

There is a high contrast them which can be enabled by adding

to the kernel command line. This is supported by both the "newt" and "gtk" frontends. TODO: the low vision parameter should get applied to gdm and the created user.

Starting from Debian installer Stretch Alpha 5, Zoom can be obtained by pressing control +/-.

TODO: bigger mouse cursor

Speech

Hardware Speech

Run

choose the GTK installer, and append

to the kernel command line. You will then get on stdio what would be spoken.

Software Speech

To test software speech synthesis, simply pass  -soundhw ac97 , and select speech synthesis in the boot menu (last item, s shortcut). As soon as the first debconf question you should get spoken feedback from the sound board.

Also test with EFI (requires ovmf from non-free):

Starting with Stretch alpha6, also test with several sound boards:

This should trigger asking for confirmation of the sound card to be used, by pressing the enter key, and this should be recorded in /etc/default/espeakup on the installed system.

One can easily check that the proper card is being used by pressing capslock-2 or capslock-1 to change the audio level, and use e.g.

to check that the level of the proper card (here the second, indexed 1) is getting changed.

After installation

On reboot into the newly-installed system, nothing more should be needed to get output again. This should work when installing without a network mirror too. If the (gnome) graphical desktop task was chosen, orca should get started to read lightdm's chooser, and sound effects should be enabled. The user created during d-i should get orca and sound effects enabled in its session too.

Hardware access

Some hardware cards can read from the vga textmode memory, the "Board Devices" section of the installation guide (https://www.debian.org/releases/stable/i386/ch05s02.en.html#idm1171) documents to boot with

 vga=normal fb=false 

This however seems to have been broken with bookworm.


CategoryDebianInstaller