Messages in this thread | | | Date | Mon, 17 Jun 2019 15:01:51 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH v3 3/4] backlight: pwm_bl: compute brightness of LED linearly to human eye. |
| |
Hi!
> > Certainly "linear" (this device will work more or less correctly if the > > userspace applies perceptual curves). Not sure about logarithmic since > > what is actually useful is something that is "perceptually linear" > > (logarithmic is merely a way to approximate that). > > > > I do wonder about a compatible string like most-detailed to > > least-detailed description. This for a PWM with the auto-generated > > tables we'd see something like: > > > > cie-1991,perceptual,non-linear > > > > For something that is non-linear but we are not sure what its tables are > > we can offer just "non-linear". > > Thanks for the feedback! > > It seems clear that we want a string for the added flexibility. I can > work on a patch with the compatible string like description you > suggested and we can discuss in the review if we want to go with that > or prefer something else.
Compatible-like string seems overly complicated.
> > Instead one valid value for the sysfs should be "unknown" and this be > > the default for drivers we have not analysed (this also makes it easy to > > introduce change here). > > An "unknown" value sounds good, it allows userspace to just do what it > did/would hace done before this attribute existed.
What about simply not presenting the attribute when we don't have the information? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html [unhandled content-type:application/pgp-signature] | |