[PATCH] powerpc: more g5 overtemp problem fix

[Benjamin Herrenschmidt]

Some G5s still occasionally experience shutdowns due to overtemp
conditions despite the recent fix. After analyzing logs from such
machines, it appears that the overtemp code is a bit too quick at
shutting the machine down when reaching the critical temperature (tmax +
8) and doesn't leave the fan enough time to actually cool it down. This
happens if the temperature of a CPU suddenly rises too high in a very
short period of time, or occasionally on boot (that is the CPUs are
already overtemp by the time the driver loads).

This patches makes the code a bit more relaxed, leaving a few seconds to
the fans to do their job before kicking the machine shutown.

Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>

--- linux-work.orig/drivers/macintosh/therm_pm72.c	2005-09-26 11:48:36.000000000 +1000
+++ linux-work/drivers/macintosh/therm_pm72.c	2005-10-07 11:03:41.000000000 +1000
@@ -923,7 +923,7 @@
 	if (temp_combi >= ((state0->mpu.tmax + 8) << 16)) {
 		printk(KERN_WARNING "Warning ! Temperature way above maximum (%d) !\n",
 		       temp_combi >> 16);
-		state0->overtemp = CPU_MAX_OVERTEMP;
+		state0->overtemp += CPU_MAX_OVERTEMP / 4;
 	} else if (temp_combi > (state0->mpu.tmax << 16))
 		state0->overtemp++;
 	else
@@ -998,7 +998,7 @@
 		printk(KERN_WARNING "Warning ! CPU %d temperature way above maximum"
 		       " (%d) !\n",
 		       state->index, temp >> 16);
-		state->overtemp = CPU_MAX_OVERTEMP;
+		state->overtemp += CPU_MAX_OVERTEMP / 4;
 	} else if (temp > (state->mpu.tmax << 16))
 		state->overtemp++;
 	else
@@ -1060,7 +1060,7 @@
 		printk(KERN_WARNING "Warning ! CPU %d temperature way above maximum"
 		       " (%d) !\n",
 		       state->index, temp >> 16);
-		state->overtemp = CPU_MAX_OVERTEMP;
+		state->overtemp = CPU_MAX_OVERTEMP / 4;
 	} else if (temp > (state->mpu.tmax << 16))
 		state->overtemp++;
 	else