9.9. My PS/2 mouse from MouseSystems doesn't seem to work.

There have been some reports that certain model of PS/2 mouse from MouseSystems works only if it is put into the ``high resolution'' mode. Otherwise, the mouse cursor may jump to the upper-left corner of the screen every so often.

Unfortunately there is no workaround for versions 2.0.X and 2.1.X. In versions 2.2 through 2.2.5, apply the following patch to /sys/i386/isa/psm.c and rebuild the kernel. See the section on building a kernel if you've no experience with building kernels.

diff -u psm.c.orig psm.c
@@ -766,6 +766,8 @@
     if (verbose >= 2)
 	log(LOG_DEBUG, "psm%d: SET_DEFAULTS return code:%04x\n",
 	    unit, i);
+    set_mouse_resolution(sc->kbdc, PSMD_RES_HIGH);
+
 #if 0
     set_mouse_scaling(sc->kbdc); 	/* 1:1 scaling */
     set_mouse_mode(sc->kbdc);		/* stream mode */
      

In versions 2.2.6 or later, specify the flags 0x04 to the PS/2 mouse driver to put the mouse into the high resolution mode. Enter UserConfig by giving the ``-c'' option at the boot prompt:

        boot: -c
      

Then, in the UserConfig command line, type:

        UserConfig> flags psm0 0x04
        UserConfig> quit
      

See the previous section for another possible cause of mouse problems.