hwmon: (applesmc) Shorten minimum wait time

The 2012 series of MacBooks have a faster SMC, and the current driver timings do not work at all. Tests show that decreasing the minimum wait time, from 64 us to 16 us, works well. Since this is still larger than the original minimum of 10 us used before 2008, there is nothing inherently problematic with changing it. The fail frequency on older machines seems to increase slightly, but not enough to be noticeable. Tested on MBA11, MBA31, MBA5,2, MBP9,2. The patch was originally written by adamski99 (ubuntuforums.org) and later tested by janhouse (bbs.archlinux.org). Signed-off-by: Henrik Rydberg <[email protected]> Signed-off-by: Guenter Roeck <[email protected]>
iegor · Jul 22, 2012 · a332bf9 · a332bf9
1 parent 08cd675
commit a332bf9
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
@@ -54,7 +54,7 @@
 #define APPLESMC_MAX_DATA_LENGTH 32
 
 /* wait up to 32 ms for a status change. */
-#define APPLESMC_MIN_WAIT	0x0040
+#define APPLESMC_MIN_WAIT	0x0010
 #define APPLESMC_MAX_WAIT	0x8000
 
 #define APPLESMC_STATUS_MASK	0x0f