Since new findings occurred and we have a better understanding of the SNC device, the development documentation is updated. Signed-off-by: Marco Chiappero <marco@xxxxxxxxxx> --- --- a/Documentation/laptops/sony-laptop.txt +++ b/Documentation/laptops/sony-laptop.txt @@ -88,15 +88,36 @@ REPEAT: DON'T DO THIS IF YOU DON'T LIKE In your kernel logs you will find the list of all ACPI methods the SNC device has on your laptop. -* For new models you will see a long list of meaningless method names, -reading the DSDT table source should reveal that: -(1) the SNC device uses an internal capability lookup table -(2) SN00 is used to find values in the lookup table -(3) SN06 and SN07 are used to call into the real methods based on - offsets you can obtain iterating the table using SN00 -(4) SN02 used to enable events. -Some values in the capability lookup table are more or less known, see -the code for all sony_call_snc_handle calls, others are more obscure. +* For new models you may see a long list of meaningless method names, +but a small subset of methods starting with "SN" is always present. These +methods define a common interface for acting with the SNC device. In +particular: + +- SN00 can be used to retrieve some informations about the SNC device; among + them, an internal capability lookup table reporting model specific features, + identified by a number called "handle", associated to an offset, to be + later used by methods SN06 and SN07. Some handles are now well known, while + some others are still a bit obscure or totally unknown. A list of known + handles can be found at http://www.absence.it/vaio-acpi/handles_list.txt + +- SN01, SN02, SN03 can be used to query, enable and disable (respectively) + the event generation for every handle, as they might trigger ACPI + notifications + +- SN04, SN05 can be used to query and clear the "event raised" flag for every + handle + +- SN06 and SN07 are used to call into the real methods, providing the handles + specific features, based on offsets you can obtain iterating the table + via SN00. They should provide the same info (or almost the same), but while + SN07 uses 32bit integers for both input and output parameters SN06 returns a + wide buffer (for both input and output values), useful for reading a few info + tables or long input parameters. + +You can have a look at a decoded, analyzed and fully explained DSDT taken from +a Sony Vaio VPCS1 model at http://www.absence.it/vaio-acpi/VPCS-findings.txt. +It should significantly help you in understanding how to use handles/offsets, +in decoding other DSDTs and in discovering new unknown features. * For old models you can see the GCDP/GCDP methods used to pwer on/off the CD drive, but there are others and they are usually different from -- To unsubscribe from this list: send the line "unsubscribe platform-driver-x86" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
