powerpc/windfarm: Fix noisy slots-fan on Xserve (rm31)

slots-fan on G5 Xserve is always running at full speed with windfarm_rm31
driver, resulting in a very high acoustic noise level. It seems the fan
parameters are incorrect, and have been copied from the Drive Bay fan
(RPM, not present on rm31) of the legacy therm_pm72 driver. This patch
changes the parameters to match the Slots fan (PWM) of therm_pm72. With
the patch, slots-fan speed drops from 99% to 19% during normal use,
and slots-temp settle to ~42'C.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
CC: <stable@vger.kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/drivers/macintosh/windfarm_rm31.c b/drivers/macintosh/windfarm_rm31.c
index 0b9a79b..82fc86a 100644 (file)
--- a/drivers/macintosh/windfarm_rm31.c
+++ b/drivers/macintosh/windfarm_rm31.c
@@ -439,15 +439,15 @@ static void backside_setup_pid(void)
 
 /* Slots fan */
 static const struct wf_pid_param slots_param = {
-       .interval       = 5,
-       .history_len    = 2,
-       .gd             = 30 << 20,
-       .gp             = 5 << 20,
-       .gr             = 0,
-       .itarget        = 40 << 16,
-       .additive       = 1,
-       .min            = 300,
-       .max            = 4000,
+       .interval       = 1,
+       .history_len    = 20,
+       .gd             = 0,
+       .gp             = 0,
+       .gr             = 0x00100000,
+       .itarget        = 3200000,
+       .additive       = 0,
+       .min            = 20,
+       .max            = 100,
 };
 
 static void slots_fan_tick(void)