[RFC/RFT] Better handling of bad xfers/interrupt delays in psmouse

[Dmitry Torokhov <dtor_core@ameritech.net>]

Hi,

The patch below attempts to better handle situation when psmouse interrupt
is delayed for more than 0.5 sec by requesting a resend. This will allow
properly synchronize with the beginning of the packet as mouse is supposed
to resend entire package.

Additionally, psmouse will also request resend if KBC indicates parity or
timeout errors. 

The patch should apply to 2.6.11-rc2+. A version of this patch for 2.6.10
is available here:

	http://www.geocities.com/dt_or/input/2_6_10/

-- 
Dmitry


===================================================================


ChangeSet@1.2006, 2005-02-05 14:33:05-05:00, dtor_core@ameritech.net
  Input: psmouse - better handle bad transfers and interrupt delays
         by requesting resend of the last packet so we don't need to
         guess if received byte is remainder of last packet or start
         of a new one.
  
  Signed-off-by: Dmitry Torokhov <dtor@mail.ru>


 psmouse-base.c |   48 +++++++++++++++++++++++++++++++++++++++++++-----
 psmouse.h      |    2 ++
 2 files changed, 45 insertions(+), 5 deletions(-)


===================================================================



diff -Nru a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c
--- a/drivers/input/mouse/psmouse-base.c	2005-02-05 14:37:51 -05:00
+++ b/drivers/input/mouse/psmouse-base.c	2005-02-05 14:37:51 -05:00
@@ -134,6 +134,42 @@
 	return PSMOUSE_FULL_PACKET;
 }
 
+static void psmouse_handle_bad_xfer(struct psmouse *psmouse, unsigned int flags)
+{
+	if (psmouse->state == PSMOUSE_ACTIVATED)
+		printk(KERN_WARNING "psmouse.c: bad data from KBC -%s%s\n",
+			flags & SERIO_TIMEOUT ? " timeout" : "",
+			flags & SERIO_PARITY ? " bad parity" : "");
+
+	if (!psmouse->resend) {
+		/*
+		 * This is first error. Try to request resend but not if we got
+		 * timeout and we are in initialize phase - there most likely no
+		 * mouse at all.
+		 */
+		if (psmouse->state > PSMOUSE_INITIALIZING || (~flags & SERIO_TIMEOUT)) {
+			if (serio_write(psmouse->ps2dev.serio, PSMOUSE_CMD_RESEND) == 0) {
+				psmouse->resend = 1;
+				psmouse->pktcnt = 0;
+			}
+		}
+	} else {
+		/*
+		 * This is second error in a row. If mouse was itialized - attempt
+		 * to rconnect, otherwise just signal failure.
+		 */
+		psmouse->resend = 0;
+		if (psmouse->state > PSMOUSE_INITIALIZING) {
+			psmouse->state = PSMOUSE_IGNORE;
+			printk(KERN_NOTICE "psmouse.c: issuing reconnect request\n");
+			serio_reconnect(psmouse->ps2dev.serio);
+		}
+	}
+
+	if (!psmouse->resend)
+		ps2_cmd_aborted(&psmouse->ps2dev);
+}
+
 /*
  * psmouse_interrupt() handles incoming characters, either gathering them into
  * packets or passing them to the command routine as command output.
@@ -149,11 +185,7 @@
 		goto out;
 
 	if (flags & (SERIO_PARITY|SERIO_TIMEOUT)) {
-		if (psmouse->state == PSMOUSE_ACTIVATED)
-			printk(KERN_WARNING "psmouse.c: bad data from KBC -%s%s\n",
-				flags & SERIO_TIMEOUT ? " timeout" : "",
-				flags & SERIO_PARITY ? " bad parity" : "");
-		ps2_cmd_aborted(&psmouse->ps2dev);
+		psmouse_handle_bad_xfer(psmouse, flags);
 		goto out;
 	}
 
@@ -168,11 +200,17 @@
 	if (psmouse->state == PSMOUSE_INITIALIZING)
 		goto out;
 
+	psmouse->resend = 0;
+
 	if (psmouse->state == PSMOUSE_ACTIVATED &&
 	    psmouse->pktcnt && time_after(jiffies, psmouse->last + HZ/2)) {
 		printk(KERN_WARNING "psmouse.c: %s at %s lost synchronization, throwing %d bytes away.\n",
 		       psmouse->name, psmouse->phys, psmouse->pktcnt);
 		psmouse->pktcnt = 0;
+		if (serio_write(serio, PSMOUSE_CMD_RESEND) == 0) {
+			psmouse->resend = 1;
+			goto out;
+		}
 	}
 
 	psmouse->last = jiffies;
diff -Nru a/drivers/input/mouse/psmouse.h b/drivers/input/mouse/psmouse.h
--- a/drivers/input/mouse/psmouse.h	2005-02-05 14:37:51 -05:00
+++ b/drivers/input/mouse/psmouse.h	2005-02-05 14:37:51 -05:00
@@ -13,6 +13,7 @@
 #define PSMOUSE_CMD_ENABLE	0x00f4
 #define PSMOUSE_CMD_DISABLE	0x00f5
 #define PSMOUSE_CMD_RESET_DIS	0x00f6
+#define PSMOUSE_CMD_RESEND	0x00fe
 #define PSMOUSE_CMD_RESET_BAT	0x02ff
 
 #define PSMOUSE_RET_BAT		0xaa
@@ -48,6 +49,7 @@
 	unsigned long last;
 	unsigned long out_of_sync;
 	enum psmouse_state state;
+	unsigned int resend;
 	char devname[64];
 	char phys[32];