diff options
| author | Ricardo Ribalda <ricardo.ribalda@gmail.com> | 2017-02-02 20:15:16 +0100 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2017-02-09 17:13:01 +0100 |
| commit | bbb27fc33d44e7b8d96369810654df4ee1837566 (patch) | |
| tree | b769e165ad52c0021054f1a048b62bd7e4fbec47 /drivers/i2c | |
| parent | f43128c75202f29ee71aa83e6c320a911137c189 (diff) | |
i2c: piix4: Request the SMBUS semaphore inside the mutex
SMBSLVCNT must be protected with the piix4_mutex_sb800 in order to avoid
multiple buses accessing to the semaphore at the same time.
Fixes: 701dc207bf55 ("i2c: piix4: Avoid race conditions with IMC")
Reported-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-piix4.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c index 73cc6799cc59..c21ca7bf2efe 100644 --- a/drivers/i2c/busses/i2c-piix4.c +++ b/drivers/i2c/busses/i2c-piix4.c @@ -592,6 +592,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr, u8 port; int retval; + mutex_lock(&piix4_mutex_sb800); + /* Request the SMBUS semaphore, avoid conflicts with the IMC */ smbslvcnt = inb_p(SMBSLVCNT); do { @@ -605,10 +607,10 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr, usleep_range(1000, 2000); } while (--retries); /* SMBus is still owned by the IMC, we give up */ - if (!retries) + if (!retries) { + mutex_unlock(&piix4_mutex_sb800); return -EBUSY; - - mutex_lock(&piix4_mutex_sb800); + } outb_p(piix4_port_sel_sb800, SB800_PIIX4_SMB_IDX); smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1); @@ -623,11 +625,11 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr, outb_p(smba_en_lo, SB800_PIIX4_SMB_IDX + 1); - mutex_unlock(&piix4_mutex_sb800); - /* Release the semaphore */ outb_p(smbslvcnt | 0x20, SMBSLVCNT); + mutex_unlock(&piix4_mutex_sb800); + return retval; } |