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authorHenrik Rydberg <rydberg@euromail.se>2008-10-18 20:27:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-20 08:52:35 -0700
commit02fcbd144d684167aa67b1d3ad68f18d265f2d08 (patch)
tree78fd75f27dc9c25d3ec3f9631d4d2a943cb48315 /drivers/hwmon/applesmc.c
parent84d2d7f2ee98dc9bd799790c89b5eb8280af2d37 (diff)
downloadlwn-02fcbd144d684167aa67b1d3ad68f18d265f2d08.tar.gz
lwn-02fcbd144d684167aa67b1d3ad68f18d265f2d08.zip
hwmon: applesmc: prolong status wait
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>
Diffstat (limited to 'drivers/hwmon/applesmc.c')
-rw-r--r--drivers/hwmon/applesmc.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index d5bd0cadbf31..9a43c4b60ea9 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -163,7 +163,7 @@ static unsigned int key_at_index;
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
* hold applesmc_lock.
*/
@@ -173,7 +173,7 @@ static int __wait_status(u8 val)
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 (debug)
printk(KERN_DEBUG