Video and sound

# 7 Video and sound

Contents of this section

## 7.1 Exiting from dosemu gives me a screen full of garbage.

Keith A Grider (`kgrider@magnus.acs.ohio-state.edu`) reported (12/5/93) that

I have seen many postings concerning this with exit from X as well as exiting from a graphic dos screen. it seems to be prevalent among ATI graphic card users as well as a few others. The problem is that the font information for the vga text screen is not being saved. The only way I have been able to fix it is to download the `vgalib-090.tar.gz` file from sunsite.unc.edu. It is (I believe) in the `pub/Linux/GCC directory`. You get a lot of stuff that is not directly used to solve this problem, but in the fonts directory that is created when you untar the file, there are 2 files of interest, runx and restorefont. Read the README file in this directory. Copy runx and restorefont to a directory in your path. when runx is used, for example, it saves the font information in tmp/fontdata. I use a file called fix which consists of the line:

       restorefont -r /tmp/fontdata

so that it is easy to 'fix' a vt when I go there from X (i.e. `ctrl-alt-f2`). This should also work for dosemu. I think the XFree86 people know about the problem and are working on a solution as this is a bit of a kluge.

## 7.2 How do I get dosemu to work with my Trident/Actix/other video card?

`[`The screen flickers violently, displays the video BIOS startup message, and hangs.]

Andrew Tridgell (`tridge@nimbus.anu.edu.au`) reported (1/29/94) that

I found with early versions it would work if I used:

       ports { 0x42 }

but that sometimes my machine would crash when it was cycling the video bios in dosemu. This is because you're allowing the VGA bios to re-program your clock, which severely stuffs with Linux.

This prompted me to write the readonly and masking patches for dosemu, which I believe are still in the latest version. I now use:

       ports { readonly 0x42 }

and it boots dosemu more slowly, but more reliably.

Tim Shnaider (`tims@kcbbs.gen.nz`) also reported (1/18/94) that

One way of fixing this is to use the GETROM program to dump your video bios to a file and edit the config file in the `/etc/dosemu` directory There will be a few video lines. Here is my video line

       video { vga console graphics chipset trident memsize 1024 vbios_file
       /etc/dosemu/vbios }

where vbios is the file generated by typing

       getrom > vbios

## 7.3 Why doesn't my soundcard software work with dosemu?

Hannu Savolainen (`hsavolai@cs.Helsinki.FI`) reported (3/21/94) that

The DOSEMU and any DOS program with it run under control of a protected mode operating system. This means that the memory is not mapped as the program expects. If it somehow manages to start DMA based recording with SB, the recorded sound doesn't find it's way to the application. It just destroys some data in the memory.

James B. MacLean (`jmaclean@fox.nstn.ns.ca`) reported (6/19/94) that

Sorry to disappoint, but at this time DOSEMU does not support directly the necessary interception of interrupts or DMA generally required for sound card access via DOSEMU :-(.

It's bound to happen at some future date though :-),

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