olpc-hardware-manager in C

[jochang]

Attached is a rewrite of olpc-hardware-manager in C (It was a 130 lines Python script). This saves about 1.8M private dirty memory according to /proc/.../smaps. I tested it on my B2 and it works fine. I hope this makes sense as this is my first time using dbus.

[marco]

Dan, can you have a look to this please? /me never used dbus in C

[dcbw]

Nice! Looks pretty good. Two comments though:

1) The timeout should be shorter for dbus_connection_read_write_dispatch(); say, 5 seconds perhaps. If it's -1, the program will block in the select/poll for quite a long time and won't exit when sent a SIGTERM for that amount of time. You can see this with dbus-monitor. Ideally when sent a SIGTERM (on system shutdown, for instance) it should shut down pretty quickly.

2) We need introspection support too; this means slightly more complicated code, since you have to deal with the "Introspect" method call. But since the service isn't supposed to be that complex, you can definitely hardcode the Introspection XML, read it in at the start of the program, and just dump it back out when you get a request for Introspect.

Thanks again; if you've got a little time, could you take a pass at doing these two things as well? If you need any help or pointers, let us know.

[jochang]

add introspection support.

[jochang]

Thanks for the review!

1) I think the default handler of SIGTERM should terminate the process immediately (just tested).

2) Introspection is added in the new attachment. I hardcoded the XML in the C file because it is small and won't change unless the C code changes also.

[jg]

Dan, is this ready to merge? If so, assign to J5.

If not, what remains?

[kimquirk]

Moving to next software release, Trial-2.

[jg]

What's the state of this vis-a-vis OHM?

[marco]

These are the keys which we are setting with hardware-manager atm.

_KEYBOARD_BRIGHTNESS_KEY = '/sys/class/leds/olpc:keyboard/brightness'

Is this in the latest hardware at all?

_DISPLAY_BRIGHTNESS_KEY = '/sys/class/backlight/dcon-bl/brightness'

Can we use ohm for this?

_DISPLAY_MODE_KEY = '/sys/devices/platform/dcon/output'

Black white/color, could this be added to ohm?

_DCON_SOURCE_KEY = '/sys/devices/platform/dcon/source' _DCON_FREEZE_KEY = '/sys/devices/platform/dcon/freeze'

Not sure about these.

_POWER_STATE_KEY = '/sys/power/state'

Is this handled by ohm already?

[warp]

We can not at this time handle keys that come over the keyboard channel via anything that doesn't work through X.

This means things like the brightness keys are going to have to stick with suger a bit longer.

This is a known limitation of the current grabbing method, and work is in progress to replace it with something better, but we'll see what happens.

(If I'm misunderstanding where the key grabbing for this would be happening, my apologies.)

[marco]

I was thinking more about having sugar call some dbus method in ohm to change brightness (similarly to what we do right now with olpc-hardware-manager). Though, if the long term plan is to handle this outside sugar maybe it's just worth waiting that happens.

[reynaldo]

Self explanatory, gets rid of keyboard LEDs related code, haven't tested but guess it works -- what else needs to be done here?

[reynaldo]

hardwaremanager.2-nokbdlight.c as a patch against hardwaremanager.2.c. Just in case you need to review the changes quickly

[cjb]

Replaced by OHM, closing.