4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guenter Roeck <linux@xxxxxxxxxxxx> commit 8358378b22518d92424597503d3c1cd302a490b6 upstream. IT8705F is known to respond on both SIO addresses. Registering it twice may result in system lockups. Reported-by: Russell King <linux@xxxxxxxxxxxxxxx> Fixes: e84bd9535e2b ("hwmon: (it87) Add support for second Super-IO chip") Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> Cc: Jean Delvare <jdelvare@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/hwmon/it87.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) --- a/drivers/hwmon/it87.c +++ b/drivers/hwmon/it87.c @@ -3115,7 +3115,7 @@ static int __init sm_it87_init(void) { int sioaddr[2] = { REG_2E, REG_4E }; struct it87_sio_data sio_data; - unsigned short isa_address; + unsigned short isa_address[2]; bool found = false; int i, err; @@ -3125,15 +3125,29 @@ static int __init sm_it87_init(void) for (i = 0; i < ARRAY_SIZE(sioaddr); i++) { memset(&sio_data, 0, sizeof(struct it87_sio_data)); - isa_address = 0; - err = it87_find(sioaddr[i], &isa_address, &sio_data); - if (err || isa_address == 0) + isa_address[i] = 0; + err = it87_find(sioaddr[i], &isa_address[i], &sio_data); + if (err || isa_address[i] == 0) continue; + /* + * Don't register second chip if its ISA address matches + * the first chip's ISA address. + */ + if (i && isa_address[i] == isa_address[0]) + break; - err = it87_device_add(i, isa_address, &sio_data); + err = it87_device_add(i, isa_address[i], &sio_data); if (err) goto exit_dev_unregister; + found = true; + + /* + * IT8705F may respond on both SIO addresses. + * Stop probing after finding one. + */ + if (sio_data.type == it87) + break; } if (!found) {