diff options
Diffstat (limited to 'Documentation/i2c')
| -rw-r--r-- | Documentation/i2c/busses/i2c-i801 | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/Documentation/i2c/busses/i2c-i801 b/Documentation/i2c/busses/i2c-i801 index 04b5de80ce4e..f426c13c63a9 100644 --- a/Documentation/i2c/busses/i2c-i801 +++ b/Documentation/i2c/busses/i2c-i801 @@ -60,6 +60,7 @@ question doesn't work as intended for whatever reason. Bit values: 0x02 disable the block buffer 0x08 disable the I2C block read functionality 0x10 don't use interrupts + 0x20 disable SMBus Host Notify Description @@ -120,16 +121,15 @@ BIOS to enable it, it means it has been hidden by the BIOS code. Asus is well known for first doing this on their P4B motherboard, and many other boards after that. Some vendor machines are affected as well. -The first thing to try is the "i2c_ec" ACPI driver. It could be that the +The first thing to try is the "i2c-scmi" ACPI driver. It could be that the SMBus was hidden on purpose because it'll be driven by ACPI. If the -i2c_ec driver works for you, just forget about the i2c-i801 driver and -don't try to unhide the ICH SMBus. Even if i2c_ec doesn't work, you +i2c-scmi driver works for you, just forget about the i2c-i801 driver and +don't try to unhide the ICH SMBus. Even if i2c-scmi doesn't work, you better make sure that the SMBus isn't used by the ACPI code. Try loading -the "fan" and "thermal" drivers, and check in /proc/acpi/fan and -/proc/acpi/thermal_zone. If you find anything there, it's likely that -the ACPI is accessing the SMBus and it's safer not to unhide it. Only -once you are certain that ACPI isn't using the SMBus, you can attempt -to unhide it. +the "fan" and "thermal" drivers, and check in /sys/class/thermal. If you +find a thermal zone with type "acpitz", it's likely that the ACPI is +accessing the SMBus and it's safer not to unhide it. Only once you are +certain that ACPI isn't using the SMBus, you can attempt to unhide it. In order to unhide the SMBus, we need to change the value of a PCI register before the kernel enumerates the PCI devices. This is done in |