diff options
| author | Guenter Roeck <linux@roeck-us.net> | 2019-04-05 08:53:08 -0700 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2019-04-15 17:19:53 -0700 |
| commit | 14b97ba5c20056102b3dd22696bf17b057e60976 (patch) | |
| tree | 9362581d01c6774f92702205fcee2ac12777b0cc /drivers/hwmon | |
| parent | e95fd518d05bfc087da6fcdea4900a57cfb083bd (diff) | |
hwmon: (vt1211) Use request_muxed_region for Super-IO accesses
Super-IO accesses may fail on a system with no or unmapped LPC bus.
Also, other drivers may attempt to access the LPC bus at the same time,
resulting in undefined behavior.
Use request_muxed_region() to ensure that IO access on the requested
address space is supported, and to ensure that access by multiple drivers
is synchronized.
Fixes: 2219cd81a6cd ("hwmon/vt1211: Add probing of alternate config index port")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
| -rw-r--r-- | drivers/hwmon/vt1211.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/hwmon/vt1211.c b/drivers/hwmon/vt1211.c index 3a6bfa51cb94..95d5e8ec8b7f 100644 --- a/drivers/hwmon/vt1211.c +++ b/drivers/hwmon/vt1211.c @@ -226,15 +226,21 @@ static inline void superio_select(int sio_cip, int ldn) outb(ldn, sio_cip + 1); } -static inline void superio_enter(int sio_cip) +static inline int superio_enter(int sio_cip) { + if (!request_muxed_region(sio_cip, 2, DRVNAME)) + return -EBUSY; + outb(0x87, sio_cip); outb(0x87, sio_cip); + + return 0; } static inline void superio_exit(int sio_cip) { outb(0xaa, sio_cip); + release_region(sio_cip, 2); } /* --------------------------------------------------------------------- @@ -1282,11 +1288,14 @@ EXIT: static int __init vt1211_find(int sio_cip, unsigned short *address) { - int err = -ENODEV; + int err; int devid; - superio_enter(sio_cip); + err = superio_enter(sio_cip); + if (err) + return err; + err = -ENODEV; devid = force_id ? force_id : superio_inb(sio_cip, SIO_VT1211_DEVID); if (devid != SIO_VT1211_ID) goto EXIT; |