On Sat, 01 Nov 2008 16:39:49 -0400 Paul Fox <[EMAIL PROTECTED]> wrote:
> hi dilinger -- one of the tasks on the EC punchlist is this one: > > "Make battery commands return 0xff (or some other invalid value) > if the battery is not present. This will be an error indication > for the kernel." > > can you point me at the kernel code that cares about this, and, in > particular if you can remember, for which commands it's most important > to have this behavior changed? i'd like to be sure i understand > the req'ts before implementing anything. > Certainly; the specific code is drivers/power/olpc_battery.c. The code that is acutally querying the battery status is olpc_bat_get_property(). Due to the current limitations of the API, we cannot simply fetch EC_BAT_ACR; every value is valid, and (aiui) the EC will simply return the last known value. This is undesirable if there's no battery present, so we currently first check EC_BAT_STATUS (for PRESENT), and then run the necessary EC command. This means that each query ends up running 2 EC commands. It would be nice to cut that down to 1. Along those lines, it would be nice if there was an error value that we could check for if the EC thinks that there is no battery present, and we run some random command that is querying for battery info. Richard and I discussed this a bunch a long time ago, but it was in person and my memory is fuzzy.. I don't remember if we came up w/ a value that would work across all EC battery commands. It would kind of suck if we had to have different error codes for different commands, but that would still be better than our current behavior. _______________________________________________ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel