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authorLinus Torvalds <torvalds@linux-foundation.org>2016-06-24 18:36:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-06-24 18:36:15 -0700
commit260eaba4eaf0daec2e21735de30de14b1d6a4d08 (patch)
tree848718353c5c4edf2846b85f5cdce2c615e28323
parented13fbbf871cf0198b283c563b6394b02b31646c (diff)
parent5ce91714b0d8c0a3ff9b858966721f508351cf4c (diff)
downloadlinux-260eaba4eaf0daec2e21735de30de14b1d6a4d08.tar.gz
Merge tag 'hwmon-for-linus-v4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull hwmon fix from Guenter Roeck: "Improve fan type detection for dell-smm to prevent kernel hang" * tag 'hwmon-for-linus-v4.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: hwmon: (dell-smm) Cache fan_type() calls and change fan detection
-rw-r--r--drivers/hwmon/dell-smm-hwmon.c25
1 files changed, 20 insertions, 5 deletions
diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 4bbc58714868..2ac87d553e22 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -238,7 +238,7 @@ static int i8k_get_fan_speed(int fan)
/*
* Read the fan type.
*/
-static int i8k_get_fan_type(int fan)
+static int _i8k_get_fan_type(int fan)
{
struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_TYPE, };
@@ -249,6 +249,17 @@ static int i8k_get_fan_type(int fan)
return i8k_smm(&regs) ? : regs.eax & 0xff;
}
+static int i8k_get_fan_type(int fan)
+{
+ /* I8K_SMM_GET_FAN_TYPE SMM call is expensive, so cache values */
+ static int types[2] = { INT_MIN, INT_MIN };
+
+ if (types[fan] == INT_MIN)
+ types[fan] = _i8k_get_fan_type(fan);
+
+ return types[fan];
+}
+
/*
* Read the fan nominal rpm for specific fan speed.
*/
@@ -782,13 +793,17 @@ static int __init i8k_init_hwmon(void)
if (err >= 0)
i8k_hwmon_flags |= I8K_HWMON_HAVE_TEMP4;
- /* First fan attributes, if fan type is OK */
- err = i8k_get_fan_type(0);
+ /* First fan attributes, if fan status or type is OK */
+ err = i8k_get_fan_status(0);
+ if (err < 0)
+ err = i8k_get_fan_type(0);
if (err >= 0)
i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN1;
- /* Second fan attributes, if fan type is OK */
- err = i8k_get_fan_type(1);
+ /* Second fan attributes, if fan status or type is OK */
+ err = i8k_get_fan_status(1);
+ if (err < 0)
+ err = i8k_get_fan_type(1);
if (err >= 0)
i8k_hwmon_flags |= I8K_HWMON_HAVE_FAN2;