Subject: Linux Busmouse HOWTO
From: [email-masked] (Mike Battersby)
Date: Mon, 25 Apr 1994 19:35:16 GMT
Newsgroups: comp.os.linux.announce,comp.os.linux.admin

Archive-name: linux/howto/busmouse
Last-modified: 18 Apr 94

		  The Busmouse HOWTO v0.9, 17 April 94
	      by Mike Battersby <[email-masked]>

[ Note:  This HOWTO document is still in BETA stage, and there are
  still some unfilled sections, particularly those on Logitech mice.  If you
  can help fill in those sections, please contact me. - Mike ]

INDEX

	0.	Introduction.
	0.1	Disclaimer.
	0.2	Feedback.
	0.3	Acknowledgements.

	1.	Determining your mouse type.
	1.1	Mouse interfaces.
	1.1.1	Inport and logitech mice.
	1.1.2	PS/2 mice.
	1.1.3	ATI-XL mice.
	1.2	Mouse protocols.

	2.	Getting your mouse working.
	2.1	Setting the mouse interrupt.
	2.1.1	Inport mice.
	2.1.2	Logitech mice.
	2.1.3	ATI-XL mice.
	2.1.4	PS/2 mice.
	2.2	Compiling the kernel.
	2.2.1	Inport, Logitech and ATI-XL mice.
	2.2.2	PS/2 mice.
	2.2.3	Selection.
	2.3	The mouse devices.
	2.4	Testing your mouse.

	3.	Using your mouse.
	3.1	Selection.
	3.2	Xfree86.
	3.3	Xfree86 and selection.

	4.	Still can't get your mouse going?

	A.	Appendices.
	A.1	selwrap.c

------------------------------------------------------------------------------
0.	Introduction.

	This document is a guide to getting your busmouse working with
	Linux.  I've written this in the hope that the ten people a week
	who post "how do I get my busmouse to work" questions in the
	comp.os.linux.* newsgroups will read it first, though I won't be
	holding my breath.

	Busmouse support has been in the kernel for as long as I can
	remember, and hasn't changed in a long time, so this document
	should be relevant to any version of Linux you're likely to have.

0.1	Disclaimer.

	The information in this document is correct to the best of my
	knowledge, but there's a always a chance I've made some mistakes,
	so don't follow everything too blindly, especially if it seems wrong.
	Nothing here should have a detrimental effect on your computer, but
	just in case I take no responsibility for any damages incurred from
	the use of the information contained herein.

	Microsoft(R) is a Trademark of Microsoft Corporation.

	[ trademark notices for other mice, anyone? - Mike ]

0.2	Feedback.

	If you find any mistakes in this document, have any comments about
	its contents or an update or addition, send them to me at the
	address listed at the top of this howto.

0.3	Acknowledgements.

	This HOWTO has been, in the spirit of Linux, a community effort.
	Many thanks go to Johan Myreen for the sections on the PS/2 mice,
	Robert T. Harris for help on the ATI-XL sections and Reuben Sumner
	for miscellaneous info and constructive criticism.

	The following people have also been invaluable in the production
	and updating of this HOWTO.

	    Daniel R. Barlow	Peter Berger	Thomas B. Fox
	    Chris Colohan	Chris Humphrey	Tim Krantz
	    Jim Van Zandt

------------------------------------------------------------------------------
1.	Determining your mouse type.

	There are two separate but important characteristics you will need
	to know about your mouse before you go on: what interface it uses
	and what protocol it uses.  The interface is the hardware aspect
	of the mouse, taking into account things like which i/o ports it
	uses and how to check if it is installed.  This is the part which
	the kernel is concerned with, so that it knows how to read data
	from the mouse.  The protocol is the software aspect of the mouse.
	Applications need to know the protocol to interpret the raw mouse
	data they receive from the kernel.

1.1	Mouse interfaces.

	The Linux kernel currently supports four different kinds of bus
	mouse interface : Inport (Microsoft), Logitech, PS/2 and ATI-XL.
	The majority of bus mice have Inport interfaces, although lately
	PS/2 interfaces are becoming more popular.  There is no surefire
	way of determining your mouse interface - mouse developers generally
	do their own thing when it comes to standards.  The following
	sections may help, otherwise you'll just have to make it up.

1.1.1	Inport mice.

	This includes most of the old style Microsoft mice which are
	shaped like a bar of dove soap.  U.S. users who have purchased
	Gateway computers should note that the mice that come with them
	are not inport mice but PS/2 mice (see below).  Inport mice
	generally connect to an interface card which plugs into the bus
	on your motherboard.  If the plug which connects your mouse cord
	to the interface card is round, has 9 pins, and a notch in one
	side you likely have an inport mouse.

1.1.2	Logitech mice.

	[ This information is based entirely on a logitech mouse manual,
	  the people involved haven't actually seen said mouse.  It may
	  be incorrect.  If you have a Logitech busmouse, please send
	  me the appropriate details. - Mike ]

	Inport mice in general appear almost exactly the same as inport
	mice.  They too connect to an interface card via a 9 pin mini-din
	connector.  Hopefully, it will have come in a Logitech box so
	you can tell it actually is a Logitech mouse.

1.1.3	PS/2 mice.

	PS/2 mice aren't really bus mice at all.  The PS/2 mouse
	interface is not on an expansion card, the mouse is connected
	to the PS/2 Auxiliary Device port on the keyboard controller.
	A PS/2 mouse port uses a 6-pin mini DIN connector, similar to
	the keyboard connector.  Many laptops also use this kind of
	interface to their trackballs - except for the connector, of
	course.

1.1.4	ATI-XL mice.

	ATI-XL mice are a variant of inport mice, with some slight
	differences.  They come on the ATI-XL combined video adaptor/mouse
	card.  Unless you know you have an ATI-XL card (and thus an ATI-XL
	mouse), you probably don't have one of these. It is possible for
	ATI-XL mice to use either the ATI-XL or inport kernel drivers,
	although the ATI-XL driver should give better results.

1.2	Mouse protocols.

	The PC world is full of different and conflicting mouse protocols.
	Fortunately, the choice for bus mice is considerable smaller than
	that for serial mice.  Inport and ATI-XL mice use the "BusMouse"
	protocol and PS/2 mice use the "PS/2" protocol.

	[ Can someone please notify me which protocol logitech uses. - Mike ]

------------------------------------------------------------------------------
2.	Getting your mouse working.

	Once you have figured out your mouse interface and protocol types,
	you're ready to proceed.

2.1	Setting the mouse interrupt.

	Now, you'll need to know which interrupt number your mouse is
	using, and make sure it doesn't conflict with any other
	peripherals you have installed.

	You should make sure that your mouse is not trying to use the same
	interrupt as any of your other devices - it is not possible for
	the mouse to share an interrupt under Linux, even though it may
	work fine under other operating systems.  Check the documentation
	for all your peripherals to see which interrupt they use.  In most
	cases IRQ4 is used for the first serial port (/dev/ttyS0), IRQ3 for
	the second (/dev/ttyS1), and IRQ5 for some SCSI adaptors.

	Note that the for ATI-XL, inport and logitech mice the kernel
	default is to use IRQ5, so if you are stuck with a pre-compiled
	kernel (eg, CD-ROM users) you will have to use that.

2.1.1   Inport and logitech mice.

        If you open up your computers case and look at the card which
        your mouse plugs into, you should notice a block of jumpers
        on the card (hopefully labeled "INTERRUPT") with positions
        for interrupt (otherwise known as IRQ) numbers 2,3,4 and 5.
        To change the interrupt simply move the jumper from its current
        position onto the correct pair of pins.

        ***************************************************
        ***     MAKE SURE YOUR COMPUTER IS TURNED OFF   ***
        ***     BEFORE CHANGING THE JUMPERS AROUND.     ***
        ***************************************************

2.1.2	ATI-XL mice.

	ATI-XL busmice have a software selectable IRQ - you should have
	received with your mouse a MS-DOS program (VSETUP.EXE) to set the
	IRQ.  In order to do so you must (temporarily) boot MS-DOS and run
	this program.  Note that the VSETUP program takes an optional
	parameter "/70" to increase the vertical refresh rate (which results
	in less flicker).  The VSETUP program also allows you to select
	either the primary or secondary mouse address - you should set
	this to the primary address or the kernel will not be able to
	detect your mouse.

	Once VSETUP has been run you must perform a hard reset for the new
	configuration to take effect.

2.1.3	PS/2 mice.

	The PS/2 mouse always uses IRQ12 -- there is no way of changing
	this (except with a soldering gun.)  In the rare case that some
	other device is using IRQ12, you'll have to rejumper that
	pheripheral to use another IRQ number.

2.2	Compiling the kernel.

	In order for your busmouse to operate correctly you will need
	to recompile your kernel with the busmouse support compiled in.

	Change to your kernel directory (here assumed to be
	'/usr/src/linux') and do a

	    make config

2.2.1	Inport, Logitech and ATI-XL mice.

	Answer 'y' to the question pertaining to your type of busmouse
	interface and 'n' to all the other busmouse questions.  For
	example, if you have an Inport mouse you should answer 'y' to

	    Microsoft busmouse support

	and 'n' to all other busmouse questions.  Answer the non-mouse
	related questions as you usually would.

	Next, edit the file '/usr/src/linux/include/linux/busmouse.h'
	and change the line which says

	    #define MOUSE_IRQ               5

	to reflect the interrupt number for your mouse (see section 2.1
	for details on finding your interrupt number).  Due to the
	vagaries of the PC architecture, if you have set your mouse to
	use interrupt 2, you must set the #define to use interrupt 9.

	Examples

	    For a mouse on interrupt 3, you should change the line to
	    read

	    #define MOUSE_IRQ               3

	    For a mouse on interrupt 2, you should change the line to
	    read

	    #define MOUSE_IRQ               9

	Next, compile your kernel as per the instructions which come
	with it, and boot from the new kernel.  You should now have
	the busmouse support correctly compiled in.

2.2.2	PS/2 mice.

	To compile the kernel with PS/2 mouse support answer 'y' to
	the question:

	    PS/2 mouse (aka "auxiliary device") support

	The PS/2 mouse driver actually supports two kinds of devices:
	the standard PS/2 Auxiliary Device controller and a special
	PS/2 mouse interface chip from Chips & Technologies which is
	used in the Texas Instruments Travelmate and Gateway Nomad
	laptops.  To compile in support for the trackballs on these
	computers, answer 'y' to the

	    C&T 82C710 mouse port support (as on TI Travelmate)

	question.  Note that you will still have to answer 'y' to the
	question about the standard PS/2 driver to even get a chance to
	answer this question, since the 82C710 driver is actually an
	add-on to the standard PS/2 mouse driver.

	When configured both for a standard PS/2 mouse device and the
	82C710 device, the driver first tries to locate a 82C710 chip
	at boot time.  Failing this, the standard driver is used
	instead, so using a kernel configured for both types of
	interface on a machine with a standard PS/2 mouse port should
	work too.  However, there has been one report of a falsely
	detected 82C710 chip, so to be on the safe side do not
	configure in support for the 82C710 if you don't need it.

	Compile your new kernel and boot from it as you normally would.

2.2.3	Selection.

	Regardless of your mouse type you should answer 'y' to the

	    Selection (cut and paste for virtual consoles)

	question if you wish to run the selection program (see section 3.1
	for more details).

2.3	The mouse devices.

	Mice under Linux are accessed via the devices in the /dev 
	directory. The following table gives a list of interface types
	and which device you should use.

	    INTERFACE	DEVICE		MAJOR	MINOR
	    ---------------------------------------------
	    Logitech	/dev/logibm	10	0
	    PS/2	/dev/psaux	10	1
	    Inport	/dev/inportbm	10	2
	    ATI-XL	/dev/atibm *	10	3

		Table 1.  Mouse devices.

	* If you are using your ATI-XL mouse with the inport driver,
	  you should use the /dev/inportbm device, not the /dev/atibm
	  device.

	The major and minor entries are the device numbers for that
	particular device.  

	If you find that you do not have these devices, you should
	create them first.  To do so, execute the following as root.

	    mknod /dev/logibm   c 10 0
	    mknod /dev/psaux    c 10 1
	    mknod /dev/inportbm c 10 2
	    mknod /dev/atibm    c 10 3

	NOTE: Some time in the recent history of Linux the names for
	  the busmouse devices have changed.  The following device names
	  have been superceded by those above and should be removed:
	  bmousems, bmouseps2, bmouseatixl, bmouselogitech.

	Many people like to create a symbolic link from their mouse
	device to /dev/mouse so that they don't have to remember which
	device they need to be using.  If you have one of the current
	Linux distributions you will almost certainly find that you have
	such a link.  If you have such a link, or create one, you should
	make sure that it is pointing to the correct device for your
	mouse.

2.4	Testing your mouse.

	Get the file 'selection-1.5.tar.gz' from your local Linux ftp
	site and compile the program 'test-mouse' within it, according
	to the instructions (all you should need to do is type 'make
	test-mouse').  Run the program like this

	    test-mouse -t <mouse arg> -m <mouse dev>

	where <mouse arg> is "bm" (without the quotes) if you use the
	BusMouse protocol, or "ps2" if you use the PS/2 protocol, and
	<mouse dev> is your mouse device name from table 1.

	If your mouse is working correctly, you should be able to
	paint on the screen by holding down the right or left mouse
	button and dragging the mouse.  Push the left and right mouse
	buttons simultaneously to exit the program.

------------------------------------------------------------------------------
3.	Using your mouse.

3.1	Selection.

	Selection is a program which allows you to do mouse based 'cut-
	and-paste' between virtual consoles under Linux.  Selection can
	be found as the file 'selection-1.5.tar.gz' at your friendly
	Linux FTP site (such as sunsite.unc.edu), and contains instructions
	for getting it compiled.  Some Linux distributions, such as 
	Slackware, come with a precompile selection binary.

	When invoking selection, use the -t switch to selection to indicate
	which protocol your mouse is using and the -m option to indicate
	which mouse device you are using.  The default is to use the
	/dev/mouse device, so you can omit the -m option if you have the
	appropriate symbolic link. For example, if you use the BusMouse
	protocol, selection should be run like this:

	    selection -t bm &

	or if you use the PS/2 protocol:

	    selection -t ps2 &

	You should then be able to cut and paste text between virtual
	consoles using the mouse buttons.  Read the documentation with
	selection, or do a 'man selection' for more information on how
	to operate it.

3.2	Xfree86.

	To use your busmouse under Xfree86, you will need to set your
	mouse protocol type in your Xconfig file. If you have a BusMouse
	protocol mouse, your Xconfig should contain (including the quotes)

	    Busmouse        "<mouse dev>"

	For PS/2 mice it should have

	    ps/2	    "<mouse dev>"

	If you have a two button mouse, it should also contain the line

	    Emulate3Buttons

	which will allow you to emulate the use of the middle mouse button
	by pressing both mouse buttons simultaneously.
	All other mouse related lines, such as "BaudRate" and "SampleRate"
	should be commented out, as these have no effect on bus mice.

3.3	Xfree86 and selection.

	Unlike serial mice, you cannot share busmice between processes.
	This means you will have to kill any copies of 'selection' (see
	section 3.1) you have running before you start up Xfree86.  If
	you try to run X with selection running, you will get errors
	like the following

	    Fatal server error:
	    Cannot open mouse (Device or resource busy)

	In section A.1 of this HOWTO is a short(ish) C program which
	will allow any user on the console to shutdown and start up
	selection as necessary.  Follow the instructions in the comments
	of the file to get it up and running.  Then, replace any references
	you have on your system to the selection program with references
	to the selwrap program (for example, in your /etc/rc? files).  You
	may alos wish to add a line like the following to your startx script,
	to make sure selection is shut down when you wish to run X.

	    /usr/sbin/selwrap off

------------------------------------------------------------------------------
4.	Still can't get your mouse going?

	So you've read through this HOWTO a dozen times, done everything
	exactly as you think you should have, and your mouse still doesn't
	work?  The best advice I can give you is this: experiment.  Sure,
	it's a pain in the posterior, but in the end the only way to find
	out what is going to work with your mouse is to try all of the
	alternatives until you have success.

	As always, if there is something you don't understand, try reading
	the manual page first and see if that helps.  If you have a specific
	question, or a problem you think I might be able to help with, feel
	free to contact me at the address listed at the top of this howto,
	and I'll see if I can help you out or point you to someone who can.

	The comp.os.linux.help newsgroup is the appropriate forum for
	discussion and/or questions regarding mice - please don't post
	questions to other groups, and especially don't crosspost
	questions to two or more of the Linux groups, they are more than
	cluttered enough as it is!  When posting, you will get a much
	better response (and much fewer flames) if you use appropriate
	Subject: and Keywords: lines.  For example:

	    Subject: BUSMICE - Gateway 2000 mouse wont work.
	    Keywords: mouse busmouse gateway

------------------------------------------------------------------------------
A.	Appendices

A.1	selwrap.c

/*
 * selwrap.c    A wrapper for selection to record the PID and allow
 *              non-root users on the console to start it up and shut
 *              it down.
 *
 *              (c) 1994 Mike Battersby <[email-masked]>
 *              You may freely distribute this program, as long as you
 *              do not change it in any way.  You are free to modify
 *              it, but may not distribute modified copies.  If you
 *              find a problem with this program, please report it to
 *              me.
 *
 *
 * Instructions:
 *      Save this file as "selwrap.c".  Edit the 'char SELECTION[]' statement
 *      below to reflect where your selection binary is kept.  If you do not
 *      use the /var/run directory for storing pid files, you should also 
 *      change the 'char PIDFILE[]' line to indicate where you want the
 *      pid file kept. Compile the program with
 *      
 *              gcc -O2 -s selwrap.c -o selwrap
 *
 *      and copy it to one of your system's bin directories (the directory
 *      you keep selection in might be best).  Then, make it setuid root
 *      with
 *
 *              chown root selwrap
 *              chmod 4111 selwrap
 *
 *      Users on the console can then start up and shut down selection
 *      with
 *
 *              selwrap on [selection commands] &
 *      and
 *              selwrap off
 *
 *      where [selection commands] are the arguments you would normally
 *      pass to selection, for example
 *
 *              selwrap on -t bm &
 *
 *      I have tried to make this program as secure as possible, but there
 *      is always a risk with setuid root programs.  It is strongly
 *      recommended that you *DO NOT* install this program if you run a
 *      public access system. Please let me know if you find any security
 *      holes in it.
 *
 */

#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <errno.h>

/* Where the selection binary is found. */
char SELECTION[] = "/usr/sbin/selection";

/* Where to put the pid file.  If you don't have /var/run, this should
 * probably be "/etc/selection.pid". */
char PIDFILE[]   = "/var/run/selection.pid";

int
on_console(void)
{
  /* Test if a user is on the console. Console tty's are assumed to be
   * major 4, minor 0-63. */
  struct stat s;
  int major, minor;
  
  if (stat(ttyname(0), &s)) {
    fprintf(stderr, "Error stat'ing tty, aborting!\n");
    exit(1);
  }
  minor = s.st_rdev & 0x00FF;
  major = (s.st_rdev & 0xFF00) >> 8;

  if ((major != 4) || (minor < 0 ) || (minor > 63)) {
    return 0;
  }
  return 1;
}

int
process_exists(int i)
{
  /* Test if a process with pid i exists by trying to get its priority */
  errno = 0;
  getpriority(PRIO_PROCESS,i);
  if (errno != ESRCH)
    return 1;
  else
    return 0;
}

int
go(char *argv[])
{
  /* Start up selection. */
  FILE *fp;
  int i;

  if ((fp = fopen(PIDFILE, "r"))) {
    fscanf(fp, "%d", &i);
    fclose(fp);
    if (process_exists(i)) {
      fprintf(stderr, "Error: selection already running, aborting.\n");
      return 1;
    }
  }
      
  if ((fp = fopen(PIDFILE, "w")) == NULL) {
    fprintf(stderr, "Error: could not open pid file %s for writing, \
                     aborting.\n", PIDFILE);
    return 1;
  }

  fprintf(fp, "%d\n", getpid());
  fclose(fp);

  argv[0] = SELECTION;
  execve(SELECTION, argv, NULL);

  fprintf(stderr, "Error: could not exec %s, aborting.\n", SELECTION);

  return 1;
}

int
stop()
{
  /* Shut down selection. */
  FILE *fp;
  pid_t pid;
  
  if ((fp = fopen(PIDFILE, "r")) == NULL) {
    fprintf(stderr, "Error: could not open file %s, aborting.\n", PIDFILE);
    return 1;
  }
  
  fscanf(fp, "%d", &pid);
  fclose(fp);
  
  if (unlink(PIDFILE)) {
    fprintf(stderr, "Error: could not remove %s.\n", PIDFILE);
  }
  
  if (kill(pid, SIGKILL)) {
    fprintf(stderr, "Error: could not kill process %d, aborting.\n", pid);
    return 1;
  }

  return 0;
}

int
main(int argc, char *argv[])
{

  if (!on_console()) {
    fprintf(stderr,"Error: must be on console to use selwrap, aborting.\n");
    return 1;
  }

  if (argc > 1) {
    if (!strcmp(argv[1], "on"))
      return go(&(argv[1]));
    else if (!strcmp(argv[1], "off"))
      return stop();
  }
  fprintf(stderr,"Usage: selwrap {on|off} [selection arguments]\n");
  return 1;
}

---------------------------------- END HOWTO ---------------------------------