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hwmon: applesmc: prolong status wait

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The time to wait for a status change while reading or writing to the SMC
ports is a balance between read reliability and system performance.  The
current setting yields rougly three errors in a thousand when
simultaneously reading three different temperature values on a Macbook
Air.  This patch increases the setting to a value yielding roughly one
error in ten thousand, with no noticable system performance degradation.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Cc: Nicolas Boichat <nicolas@boichat.ch>
Cc: Riki Oktarianto <rkoktarianto@gmail.com>
Cc: Mark M. Hoffman <mhoffman@lightlink.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Henrik Rydberg 2008-10-18 20:27:39 -07:00 committed by Linus Torvalds
parent 84d2d7f2ee
commit 02fcbd144d
1 changed files with 2 additions and 2 deletions
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4
drivers/hwmon/applesmc.c
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@ -163,7 +163,7 @@ static unsigned int key_at_index;
static struct workqueue_struct *applesmc_led_wq; static struct workqueue_struct *applesmc_led_wq;
/* /*
* __wait_status - Wait up to 2ms for the status port to get a certain value * __wait_status - Wait up to 10ms for the status port to get a certain value
* (masked with 0x0f), returning zero if the value is obtained. Callers must * (masked with 0x0f), returning zero if the value is obtained. Callers must
* hold applesmc_lock. * hold applesmc_lock.
*/ */
@ -173,7 +173,7 @@ static int __wait_status(u8 val)
val = val & APPLESMC_STATUS_MASK; val = val & APPLESMC_STATUS_MASK;
for (i = 0; i < 200; i++) { for (i = 0; i < 1000; i++) {
if ((inb(APPLESMC_CMD_PORT) & APPLESMC_STATUS_MASK) == val) { if ((inb(APPLESMC_CMD_PORT) & APPLESMC_STATUS_MASK) == val) {
if (debug) if (debug)
printk(KERN_DEBUG printk(KERN_DEBUG