Messages in this thread | | | Date | Thu, 9 Jun 2022 19:45:11 +0200 | From | Stephen Kitt <> | Subject | Re: [PATCH] fbdev: atmel_lcdfb: Rework backlight status updates |
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Hi Sam, Daniel,
On Thu, 9 Jun 2022 19:30:57 +0200, Sam Ravnborg <sam@ravnborg.org> wrote: > thanks for taking care of all these backlight simplifications - this > really helps to make the code simpler and more readable.
You’re welcome! I noticed fb_blank was deprecated and near enough unused, and started digging...
> On Thu, Jun 09, 2022 at 10:54:12AM +0100, Daniel Thompson wrote: > > On Wed, Jun 08, 2022 at 10:56:23PM +0200, Stephen Kitt wrote: > > > Instead of checking the state of various backlight_properties fields > > > against the memorised state in atmel_lcdfb_info.bl_power, > > > atmel_bl_update_status() should retrieve the desired state using > > > backlight_get_brightness (which takes into account the power state, > > > blanking etc.). This means the explicit checks using props.fb_blank > > > and props.power can be dropped. > > > > > > Then brightness can only be negative if the backlight is on but > > > props.brightness is negative, so the test before reading the > > > brightness value from the hardware can be simplified to > > > (brightness < 0). > > > > props.brightness should always be in the interval 0..max_brightness. > > > > This is enforced by the main backlight code (and APIs to set the > > brightness use unsigned values). Thus props.brightness could only be > > negative is the driver explicitly sets a negative value as some kind of > > placeholder (which this driver does not do). > > > > I don't think there is any need to keep this logic. > > Daniel is right - please drop the "if (brightness < 0)" logic. > I have looked a bit on the datasheet in my attempt to do a drm version > of this driver - something that I am yet to succeed and the backlight > core avoid any negative values.
Thanks for the reviews!
I’ve prepared a v2 without the (brightness < 0) logic, I’m about to submit it.
Regards,
Stephen [unhandled content-type:application/pgp-signature] | |