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Diffstat (limited to 'Documentation/thinkpad-acpi.txt')
| -rw-r--r-- | Documentation/thinkpad-acpi.txt | 40 |
1 files changed, 34 insertions, 6 deletions
diff --git a/Documentation/thinkpad-acpi.txt b/Documentation/thinkpad-acpi.txt index 1a42b77e2ece..0e4e053cface 100644 --- a/Documentation/thinkpad-acpi.txt +++ b/Documentation/thinkpad-acpi.txt @@ -1,7 +1,7 @@ ThinkPad ACPI Extras Driver Version 0.14 - March 26th, 2007 + April 21st, 2007 Borislav Deianov <borislav@users.sf.net> Henrique de Moraes Holschuh <hmh@hmh.eng.br> @@ -67,11 +67,39 @@ thinkpad-specific bay functionality. Features -------- -The driver creates the /proc/acpi/ibm directory. There is a file under -that directory for each feature described below. Note that while the -driver is still in the alpha stage, the exact proc file format and -commands supported by the various features is guaranteed to change -frequently. +The driver exports two different interfaces to userspace, which can be +used to access the features it provides. One is a legacy procfs-based +interface, which will be removed at some time in the distant future. +The other is a new sysfs-based interface which is not complete yet. + +The procfs interface creates the /proc/acpi/ibm directory. There is a +file under that directory for each feature it supports. The procfs +interface is mostly frozen, and will change very little if at all: it +will not be extended to add any new functionality in the driver, instead +all new functionality will be implemented on the sysfs interface. + +The sysfs interface tries to blend in the generic Linux sysfs subsystems +and classes as much as possible. Since some of these subsystems are not +yet ready or stabilized, it is expected that this interface will change, +and any and all userspace programs must deal with it. + + +Notes about the sysfs interface: + +Unlike what was done with the procfs interface, correctness when talking +to the sysfs interfaces will be enforced, as will correctness in the +thinkpad-acpi's implementation of sysfs interfaces. + +Also, any bugs in the thinkpad-acpi sysfs driver code or in the +thinkpad-acpi's implementation of the sysfs interfaces will be fixed for +maximum correctness, even if that means changing an interface in +non-compatible ways. As these interfaces mature both in the kernel and +in thinkpad-acpi, such changes should become quite rare. + +Applications interfacing to the thinkpad-acpi sysfs interfaces must +follow all sysfs guidelines and correctly process all errors (the sysfs +interface makes extensive use of errors). File descriptors and open / +close operations to the sysfs inodes must also be properly implemented. Driver version -- /proc/acpi/ibm/driver --------------------------------------- |