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From: Jacek A. <j.a...@sa...> - 2016-11-24 16:21:31
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On 11/24/2016 04:36 PM, Pali Rohár wrote: > On Thursday 24 November 2016 16:32:06 Jacek Anaszewski wrote: >> Since it has been reported that POLLPRI notifications on brightness >> file can lead to increased power consumption, and having my above >> statement I don't think that it is a good idea to use brightness >> file for this. > > How is brightness file different from others that it cannot issue > POLLPRI notification? > > I understood that problem is there in case that LED level is changed too > many times per second (like by CPU trigger). > > If this is not that problem can you describe real issue, why we cannot > use POLLPRI for brightness file? It would be inconsistent not to notify all brightness changes on brightness file. We should notify all of them or none. >>> Yes, how triggers interact with brightness file, what happen when you >>> write 0 on active trigger, >> >> There is already a patch in linux-next adding the following: >> >> >> + Writing 0 to this file clears active trigger. >> + >> + Writing non-zero to this file while trigger is active changes the >> + top brightness trigger is going to use. >> + > > Great! > >>> what happen when you read brightness file >>> with active trigger / without trigger. >>> >> >> Yes, this needs to be covered too. > -- Best regards, Jacek Anaszewski |
