A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-28 02:32:09 -04:00
Code Issues Projects Releases Packages Wiki Activity

hpet: fix the possibility of insane return value of hpet_calibrate() against SMI

Browse source 
hpet_calibrate() has a possibility of miss-calibration due to SMI.  If SMI
interrupts in the while loop of calibration, then return value will be
big.  This change calibrates until stabilizing by the return value with a
small value.

[[email protected]: trivial style tweaks]
Signed-off-by: Yasunori Goto <[email protected]>
Acked-by: Clemens Ladisch <[email protected]>
Acked-by: Vojtech Pavlik <[email protected]>
Cc: Robert Picco <[email protected]>
Cc: Venkatesh Pallipadi <[email protected]>
Cc: Ingo Molnar <[email protected]>
Acked-by: Paul Gortmaker <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Yasunori Goto 2009-04-02 16:58:31 -07:00 • committed by Linus Torvalds
commit 303d379c54
1 changed files with 21 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

22
drivers/char/hpet.c
View file

@ -713,7 +713,7 @@ static struct ctl_table_header *sysctl_header;
*/
#define TICK_CALIBRATE (1000UL)
static unsigned long hpet_calibrate(struct hpets *hpetp)
static unsigned long __hpet_calibrate(struct hpets *hpetp)
{
struct hpet_timer __iomem *timer = NULL;
unsigned long t, m, count, i, flags, start;
@ -750,6 +750,26 @@ static unsigned long hpet_calibrate(struct hpets *hpetp)
return (m - start) / i;
}
static unsigned long hpet_calibrate(struct hpets *hpetp)
{
unsigned long ret = -1;
unsigned long tmp;
/*
* Try to calibrate until return value becomes stable small value.
* If SMI interruption occurs in calibration loop, the return value
* will be big. This avoids its impact.
*/
for ( ; ; ) {
tmp = __hpet_calibrate(hpetp);
if (ret <= tmp)
break;
ret = tmp;
}
return ret;
}
int hpet_alloc(struct hpet_data *hdp)
{
u64 cap, mcfg;