On Thu, 2009-08-06 at 15:13 +0800, Pavel Machek wrote: > > > > No, > > > > For a ALS policy, user space should set a brightness level as the base > > > > point, i.e. the backlight when display adjustment is 100. > > > > and then uses the adjustment values gotten from this mappings to > > > > calculate the actual brightness level the display should be put in. > > > > > > Ok, so just make the code return only the "adjustement" -- userspace > > > does not really need to know "illuminance" and you can do the mapping > > > in the kernel AFAICT. > > > > > > > ALS exports > > 1. the current ambient light illuminance > > 2. the mappings > > > > Backlight device exports > > 1. the brightness levels. > > > > User space needs to: > > 1. set a brightness level as the base point > > 2. read the current ambient light illuminance from ALS device > > 3. read the ambient light illuminance to display adjustment mappings > > 4. calculate a proper brightness level we should set. > > > > For example, if we set brightness 6 as the default brightness, i.e. the > > brightness level when ambient light illuminance is 300. > > Now we walk outdoors, and the current illuminance is 1000, > > then we should set the new_brightness_level to (6 * 150%) > > Yes, so just export > > ALS exports > 1. the current ambient light illuminance > 2. the current mapped ambient light illuminance > In fact, only one attribute is enough. The ALS driver can query the current illuminance, parse the mapping and only export the display luminance adjustment values to user space. > Backlight device exports > 1. the brightness levels. > > User space needs to: > 1. set a brightness level as the base point > 2. read the current mapped ambient light illuminance from ALS device > 3. calculate a proper brightness level we should set. > then user space just needs to 1. set a brightness level as the base point 2. get the display adjustment value and calculate a proper brightness level at any time. this is easier, but it makes me feel that this doesn't look like an _ALS_ device any more. We still should export some ALS properties to user space, shouldn't we? Could you please look at the documentation about ALS sysfs class in the patch I sent out just now, and comment on that one please? thanks! thanks, rui -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
