work around incorrect csp for trackpad

Reference: /n/atom/patch/applied/usbtrackpadfix
Date: Wed May 14 18:19:49 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/usb/kb/hid.h	Wed May 14 18:19:49 2014
+++ /sys/src/cmd/usb/kb/hid.h	Wed May 14 18:19:49 2014
@@ -11,6 +11,7 @@
 
 	/* HID class subclass protocol ids */
 	PtrCSP		= 0x020103,	/* mouse.boot.hid */
+	Ptr2CSP		= 0x000003,	/* broken trackpoint */
 	KbdCSP		= 0x010103,	/* keyboard.boot.hid */
 
 	/* Requests */
--- /sys/src/cmd/usb/kb/kb.c	Wed May 14 18:19:49 2014
+++ /sys/src/cmd/usb/kb/kb.c	Wed May 14 18:19:49 2014
@@ -907,7 +907,7 @@
 int
 kbmain(Dev *d, int argc, char* argv[])
 {
-	int bootp, i, kena, pena, accel, devid, debug;
+	int bootp, i, kena, pena, accel, devid, debug, csp;
 	Ep *ep;
 	KDev *kd;
 	Usbdev *ud;
@@ -963,7 +963,8 @@
 			continue;
 		if(ep->type != Eintr || ep->dir != Ein && ep->dir != Eboth)
 			continue;
-		if(kena && ep->iface->csp == KbdCSP){
+		csp = ep->iface->csp;
+		if(kena && csp == KbdCSP){
 			kd = d->aux = emallocz(sizeof(KDev), 1);
 			kd->accel = 0;
 			kd->bootp = 1;
@@ -982,7 +983,7 @@
 				free(kd);
 			}
 		}
-		if(pena && ep->iface->csp == PtrCSP){
+		if(pena && (csp == PtrCSP || csp == Ptr2CSP)){
 			kd = d->aux = emallocz(sizeof(KDev), 1);
 			kd->accel = accel;
 			kd->bootp = bootp;
--- /sys/src/cmd/usb/kb/main.c	Wed May 14 18:19:49 2014
+++ /sys/src/cmd/usb/kb/main.c	Wed May 14 18:19:49 2014
@@ -26,7 +26,7 @@
 	char args[Arglen];
 	char *as, *ae;
 	int accel, pena, devid;
-	int csps[] = { KbdCSP, PtrCSP, 0 };
+	int csps[] = { KbdCSP, PtrCSP, Ptr2CSP, 0 };
 
 	quotefmtinstall();
 	pena = 1;