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Commit 14b97ba5 authored by Guenter Roeck's avatar Guenter Roeck
Browse files

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: 2219cd81 ("hwmon/vt1211: Add probing of alternate config index port")
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent e95fd518

drivers/hwmon/vt1211.c

+12 −3
Original line number Diff line number Diff line
@@ -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 @@ static int __init vt1211_device_add(unsigned short address) 


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;