Problems with C&T 82C710 mouse

Goncal Badenes (
Fri, 15 Sep 1995 19:18:45 +0200 (MET DST)


I am having problems with the kernel support for the C&T 82C710 chip
(mouse driver). That's the one present on TI Travelmate notebooks.

In fact, the automatic detection of the chip is broken (at least for my
machine) since 1.1.88. Kernel versions lower than that could find the
chip without any problems, but it seems that the serial driver changes
in 1.1.88 touched something that made the detection of the chip
impossible. Since then, all kernel versions I have tried (including
1.2.X) fail to detect the chip.

The failure can be detected at boot time, when instead of

82C710 type pointing device detected -- driver installed.

a message telling that a PS/2 type pointing device has been detected.

Until now I "solved" the problem by bypassing automatic detection and
forcing the installation of the 82C710 chip driver. I used the following
patch on the file linux/drivers/char/psaux.c:

< /* int qp_found = 0; */
< int qp_found = 1;

> 	int qp_found = 0;
< /*        if ((qp_found = probe_qp())) { */
<         if (qp_found) { /* Force 82C710 detection! */
< 	        printk("82C710 type pointing device detected -- driver installed.\n");
> 	if ((qp_found = probe_qp())) {
> 		printk("82C710 type pointing device detected -- driver installed.\n");

But now things became worse, and both 1.3.26 and 1.3.27 fail to work at all. Automatic detection still does not work and the kludge I was using stopped working, too.

Now, trying to access the mouse gives a "No such device" error:

bash# cat < /dev/psaux bash: /dev/mouse: No such device

Unfortunately, my (lack of) knowledge about the internal workings of the serial driver prevents me from doing the necessary modifications and providing a patch which solves the problem :-(

Best regards,


P.S. There are other users with exactly the same problem, so I think that this is not a hardware problem

Goncal Badenes, PhD                     Tel: +32 16 281517
IMEC                                    Fax: +32 16 281214
Advanced Semiconductor Processing
0.25um CMOS Process Integration
Kapeldreef 75                           e-mail:
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