On Fri, 20 Dec 2002, Joe Drew wrote:
> I can't speak to how this would affect long-term reliability, but in an
> attempt to un-crap the SMBus on this card, I've tried adding the KILL
> flag bit to before the host busy wait in piix4_transaction().
> Unfortunately, it doesn't work - I get "KILL failed."
I would like to see if the KILL mechanism works in the first place, on
an un-crapped bus. Maybe we must keep KILL flag set for some time to let
host issue Stop condition on bus. Should not hurt to try.
> In addition, when the sensor modules were running, they returned all
> (binary) ones in values, too. Is that a common occurrence when the bus
> is locked up?
The return code -1 is cast to all binary ones. This is unfortunate
standard behaviour on some (if not all) sensors, and means there
was a SMBus transaction error, not necessarily bus lockup.
--
Ky?sti M?lkki
kmalkki at cc.hut.fi
-------------- next part --------------
--- i2c-piix4.c.orig Sat Oct 12 15:43:13 2002
+++ i2c-piix4.c Sat Dec 21 11:17:54 2002
@@ -353,28 +353,29 @@
#endif
/* Make sure the SMBus host is ready to start transmitting */
- if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
+ while ( ((temp = inb_p(SMBHSTSTS)) != 0x00) && (timeout++ < 5)) {
#ifdef DEBUG
- printk(KERN_DEBUG "i2c-piix4.o: SMBus busy (%02x). Resetting... \n",
+ printk(KERN_DEBUG "i2c-piix4.o: SMBus busy (%02x). Waiting... \n",
temp);
#endif
- outb_p(temp, SMBHSTSTS);
- if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
+ piix4_do_pause(HZ/10);
+ }
+ if (timeout >= 5) {
#ifdef DEBUG
- printk(KERN_ERR "i2c-piix4.o: Failed! (%02x)\n", temp);
+ printk(KERN_ERR "i2c-piix4.o: SMBus busy timeout! (%02x)\n", temp);
#endif
- return -1;
- } else {
+ return -1;
+ } else if (timeout) {
#ifdef DEBUG
- printk(KERN_DEBUG "i2c-piix4.o: Successfull!\n");
+ printk(KERN_DEBUG "i2c-piix4.o: SMBus released after %d attempts\n", timeout);
#endif
- }
}
/* start the transaction by setting bit 6 */
outb_p(inb(SMBHSTCNT) | 0x040, SMBHSTCNT);
/* We will always wait for a fraction of a second! (See PIIX4 docs errata) */
+ timeout=0;
do {
piix4_do_pause(1);
temp = inb_p(SMBHSTSTS);
@@ -413,6 +414,30 @@
if (inb_p(SMBHSTSTS) != 0x00)
outb_p(inb(SMBHSTSTS), SMBHSTSTS);
+ if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
+#ifdef DEBUG
+ printk
+ (KERN_ERR "i2c-piix4.o: Trying KILL at end of transaction (%02x)\n",
+ temp);
+#endif
+ /* KILL */
+ outb_p(inb(SMBHSTCNT) | 0x02, SMBHSTCNT);
+ timeout = 0;
+ while ( !(temp = inb_p(SMBHSTSTS) & 0x10) && (timeout++ < 5)) {
+#ifdef DEBUG
+ printk(KERN_DEBUG "i2c-piix4.o: SMBus busy (%02x). Waiting... \n",
+ temp);
+#endif
+ piix4_do_pause(HZ/10);
+ }
+ outb_p(temp = inb_p(SMBHSTSTS), SMBHSTSTS);
+#ifdef DEBUG
+ if (temp)
+ printk(KERN_ERR "i2c-piix4.o: KILL failed (%02x)\n", temp);
+#endif
+ /* UNKILL */
+ outb_p(inb(SMBHSTCNT) &~ 0x02, SMBHSTCNT);
+ }
#ifdef DEBUG
if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
printk
