[Qemu-devel] Keyboard issues, native DOS mode

[Qemu-devel] Keyboard issues, native DOS mode

[David Burrows]

Hi all,

Some of you will already be aware of this issue, as it has been discussed 
on #qemu on freenode (irc).  This issue is as follows.

http://www.haltech.com.au/downloads/E6GMv509.zip

This particular application, which is used to tune the aftermarket fuel 
injection computer in my car, has a problem when running in native
DOS mode, where two keypresses are received, instead of just the one that
was actually pressed.  In particular I'm referring to the cursor keys.

Interestingly enough, this behaviour is not exhibited when the program is 
run from within either win98se or win2k.  However, as this program needs 
direct access to the serial port, this is not a desirable workaround.

You can test this by selecting offline mode when starting the application. 
Press ALT F to get to the file menu, and try navigating around with the 
cursor keys.

Apologies that this issue has already been posted in the forums under the 
Linux section, however as this is of a more technical nature I thought it 
would be best directed towards the developer's list.

It might be of note that I'm using a debian sid system, but I've also 
tried it on Ubuntu Breezy, and several others have reproduced the same 
result.

Regards,

David B.

Re: [Qemu-devel] Keyboard issues, native DOS mode

[Jim C. Brown]

[-- Attachment #1: Type: text/plain, Size: 1162 bytes --]

On Tue, Mar 14, 2006 at 07:40:58PM +1100, David Burrows wrote:
> Hi all,
> 
> This particular application, which is used to tune the aftermarket fuel 
> injection computer in my car, has a problem when running in native
> DOS mode, where two keypresses are received, instead of just the one that
> was actually pressed.  In particular I'm referring to the cursor keys.

Patch attached.

> 
> Interestingly enough, this behaviour is not exhibited when the program is 
> run from within either win98se or win2k.

w2k (don't say win2k or win98 - see RMS on why) emulates its own kbd controller,
Hence this bus would never have manifested.

Not sure how w98 handles this but I'd guess it does emulation as well, so you
don't see the bug for the same reason.

> 
> It might be of note that I'm using a debian sid system, but I've also 
> tried it on Ubuntu Breezy, and several others have reproduced the same 
> result.
> 

Shouldn't matter, as it's a qemu bug so it'd be present on all versions (in fact
it'd be present when running DOS in qemu on a Windows host iiuc).

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.

[-- Attachment #2: snadge-w.diff --]
[-- Type: text/plain, Size: 611 bytes --]

--- ps2.c.orig	Tue Mar 14 19:46:15 2006
+++ ps2.c	Tue Mar 14 19:43:58 2006
@@ -146,6 +146,7 @@
     PS2State *s = (PS2State *)opaque;
     PS2Queue *q;
     int val, index;
+static int hahaha = 0;
     
     q = &s->queue;
     if (q->count == 0) {
@@ -156,7 +157,16 @@
         if (index < 0)
             index = PS2_QUEUE_SIZE - 1;
         val = q->data[index];
+if (hahaha){
+val = 0;
+hahaha = 0;
+printf("many badness\n");
+} else
+{ hahaha = 1;
+printf("some badness\n");
+}
     } else {
+hahaha = 0;
         val = q->data[q->rptr];
         if (++q->rptr == PS2_QUEUE_SIZE)
             q->rptr = 0;

Re: [Qemu-devel] Keyboard issues, native DOS mode

[Jim C. Brown]

On Tue, Mar 14, 2006 at 08:01:00PM -0500, Jim C. Brown wrote:
> On Tue, Mar 14, 2006 at 07:40:58PM +1100, David Burrows wrote:
> > Hi all,
> > 
> > This particular application, which is used to tune the aftermarket fuel 
> > injection computer in my car, has a problem when running in native
> > DOS mode, where two keypresses are received, instead of just the one that
> > was actually pressed.  In particular I'm referring to the cursor keys.
> 
> Patch attached.

Incidently, I tried to fix this by removing the bugfix for EMM886.EXE completely
but this just caused your program to break. It didn't appear to recieve any
keypresses whatsoever. Strange.

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.