jmunsin@iki.fi [PATCH] I2C: fix it87 sensor driver stops CPU fan ChangeSet 1.2329.2.7, 2005/01/14 14:43:30-08:00, jmunsin@iki.fi [PATCH] I2C: fix it87 sensor driver stops CPU fan > 2* I would then add a check to the it87 driver, which completely disables > the fan speed control interface if the initial configuration looks weird > (all fans supposedly stopped and polarity set to "active low"). This > should protect users of the driver who have a faulty BIOS. > > When a bogus configuration is detected, we would of course complain in > the logs and invite the user to complain to his/her motherboard maker > too. Here is it87.c_2.6.10-jm4-detect_broken_bios_20050112.diff implementing this. It goes on top of the previous patch. - detects broken bioses, disables the pwm for them and prints a message - fixes an unrelated minor bug in set_fan_div() Signed-off-by: Jean Delvare Signed-off-by: Jonas Munsin Signed-off-by: Greg Kroah-Hartman drivers/i2c/chips/it87.c | 29 ++++++++++++++++++++++------- 1 files changed, 22 insertions(+), 7 deletions(-) diff -Nru a/drivers/i2c/chips/it87.c b/drivers/i2c/chips/it87.c --- a/drivers/i2c/chips/it87.c 2005-01-17 13:20:25 -08:00 +++ b/drivers/i2c/chips/it87.c 2005-01-17 13:20:25 -08:00 @@ -500,7 +500,7 @@ else data->fan_div[nr] = 3; } - val = old & 0x100; + val = old & 0x80; val |= (data->fan_div[0] & 0x07); val |= (data->fan_div[1] & 0x07) << 3; if (data->fan_div[2] == 3) @@ -703,6 +703,8 @@ int err = 0; const char *name = ""; int is_isa = i2c_is_isa_adapter(adapter); + int enable_pwm_interface; + int tmp; if (!is_isa && !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) @@ -812,6 +814,17 @@ /* Initialize the IT87 chip */ it87_init_client(new_client, data); + /* Some BIOSes fail to correctly configure the IT87 fans. All fans off + * and polarity set to active low is sign that this is the case so we + * disable pwm control to protect the user. */ + enable_pwm_interface = 1; + tmp = it87_read_value(new_client, IT87_REG_FAN_CTL); + if ((tmp & 0x87) == 0) { + enable_pwm_interface = 0; + dev_info(&new_client->dev, + "detected broken BIOS defaults, disabling pwm interface"); + } + /* Register sysfs hooks */ device_create_file(&new_client->dev, &dev_attr_in0_input); device_create_file(&new_client->dev, &dev_attr_in1_input); @@ -860,12 +873,14 @@ device_create_file(&new_client->dev, &dev_attr_fan2_div); device_create_file(&new_client->dev, &dev_attr_fan3_div); device_create_file(&new_client->dev, &dev_attr_alarms); - device_create_file(&new_client->dev, &dev_attr_pwm1_enable); - device_create_file(&new_client->dev, &dev_attr_pwm2_enable); - device_create_file(&new_client->dev, &dev_attr_pwm3_enable); - device_create_file(&new_client->dev, &dev_attr_pwm1); - device_create_file(&new_client->dev, &dev_attr_pwm2); - device_create_file(&new_client->dev, &dev_attr_pwm3); + if (enable_pwm_interface) { + device_create_file(&new_client->dev, &dev_attr_pwm1_enable); + device_create_file(&new_client->dev, &dev_attr_pwm2_enable); + device_create_file(&new_client->dev, &dev_attr_pwm3_enable); + device_create_file(&new_client->dev, &dev_attr_pwm1); + device_create_file(&new_client->dev, &dev_attr_pwm2); + device_create_file(&new_client->dev, &dev_attr_pwm3); + } if (data->type == it8712) { device_create_file_vrm(new_client);