On Monday, December 21, 2015 at 11:08:55 AM, Gabriele Mazzotta wrote: > 2015-12-21 0:33 GMT+01:00 Marek Vasut <marex@xxxxxxx>: > > On Saturday, December 19, 2015 at 05:09:33 PM, Jonathan Cameron wrote: > >> On 17/12/15 20:32, Gabriele Mazzotta wrote: > >> > Hi, > >> > > >> > I have a question regarding the acpi-als driver. > >> > > >> > Currently acpi-als uses IIO_CHAN_INFO_RAW to report the data coming > >> > from the sensor. However, as per the ACPI specification [1] (section > >> > 9.2.2), these values represent the ambient light illuminance expressed > >> > in lux. Wouldn't IIO_CHAN_INFO_PROCESSED be more appropriate in this > >> > case as the data are in theory pre-processed by the firmware of the > >> > platform? > >> > >> Looks like it to me as well. Cc'd Marek and Martin. > > > > Gotta say, I haven't looked at ACPI for a while now. My impression is > > that these data are RAW and the system software can adjust them based on > > the values in _ALR table. The result of that would be _PROCESSED I > > think. But I might be entirely wrong. > > I'm not sure of this. _ALR returns an ambient light illuminance to > display luminance mapping that suggests how to adjust the screen > backlight. There are then _ALC and _ALT which report the ambient light > color chromaticity and the ambient light color temperature respectively. ALC and ALT are optional I believe (at least I recall my crappy old hardware on which I first implemented this didn't have them at all). Thanks for clarifying what the ALR means, I never really understood how that was supposed to work in the first place . > So I don't think there are adjustments we can perform. If you think _PROCESSED is more appropriate, I will not oppose it. At this point, you are the bigger expert on ALS :) > >> > [1] http://www.acpi.info/DOWNLOADS/ACPIspec50.pdf > >> > > >> > Regards, > >> > Gabriele > >> > -- > >> > To unsubscribe from this list: send the line "unsubscribe linux-iio" > >> > in the body of a message to majordomo@xxxxxxxxxxxxxxx > >> > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > Best regards, > > Marek Vasut Best regards, Marek Vasut -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
