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Commit bbb27fc3 authored by Ricardo Ribalda Delgado's avatar Ricardo Ribalda Delgado Committed by Wolfram Sang
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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: 701dc207 ("i2c: piix4: Avoid race conditions with IMC")
Reported-by: default avatarJean Delvare <jdelvare@suse.de>
Signed-off-by: default avatarRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: default avatarJean Delvare <jdelvare@suse.de>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent f43128c7

drivers/i2c/busses/i2c-piix4.c

+7 −5
Original line number Diff line number Diff line
@@ -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;

}