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authorHenrique de Moraes Holschuh <hmh@hmh.eng.br>2006-11-24 11:47:08 -0200
committerLen Brown <len.brown@intel.com>2006-12-07 01:38:38 -0500
commit60eb0b35a9cc3400251cb4028d100e350649cf8a (patch)
tree2f655a273572e46b6c4f662071d027e57cad1bcf /drivers/acpi/event.c
parenta26f878abcd0491906b5bbac8dd174f27019e907 (diff)
ACPI: ibm-acpi: Implement direct-ec-access thermal reading modes for up to 16 sensors
This patch extends ibm-acpi to support reading thermal sensors directly through ACPI EC register access. It uses a DMI match to detect ThinkPads with a new-style embedded controller, that are known to have forward- compatible register maps and use 0x00 to fill in non-used registers and export thermal sensors at EC offsets 0x78-7F and 0xC0-C7. Direct ACPI EC register access is implemented for 8-sensor and 16-sensor new-style ThinkPad controller firmwares as an experimental feature. The code does some limited sanity checks on the temperatures read through EC access, and will default to the old ACPI TMP0-7 mode if anything is amiss. Userspace ABI is not changed for 8 sensors, but /proc/acpi/ibm/thermal is extended for 16 sensors if the firmware supports 16 sensors. A documentation update is also provided. The information about the ThinkPad register map was determined by studying ibm-acpi "ecdump" output from various ThinkPad models, submitted by subscribers of the linux-thinkpad mailinglist. Futher information was gathered from the DSDT tables, as they describe the EC register map in recent ThinkPads. DSDT source shows that TMP0-7 access and direct register access are actually the same thing on these firmwares, but unfortunately IBM never did update their DSDT EC register map to export TMP8-TMP15 for the second range of sensors. Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
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