this is just regurgitating the manufacturer's claim. I believe it when I see it. Most of display energy use is to turn on the OLED/backlight. They're claiming, because our display flickers less, it's 48% more efficient now.
A low refresh rate probably still requires the same display-side framebuffer as PSR.
With conventional PSR, I think the goal is to power off the link between the system framebuffer and the display controller and potentially power down the system framebuffer and GPU too. This may not be beneficial unless it can be left off long enough, and there may be substantial latency to fire it all back up. You do it around sleep modes where you are expecting a good long pause.
Targeting 1 Hz sounds like actually planning to clock down the link and the system framebuffer so they can run sustain low bandwidth in a more steady state fashion. Presumably you also want to clock down any app and GPU work to not waste time rendering screens nobody will see. This seems just as challenging, i.e. having a "sync to vblank" that can adapt all the way down to 1 Hz?
But why 1hz? Can’t the panel just leave the pixels on the screen for an arbitrary length of time until something triggers refresh? Only a small amount of my screen changes as I’m typing.
Haven't phones, watches and tablets been using low refresh rates to enable battery improvements for a while?
The Apple Watch Series 5 (2019) has a refresh rate down to 1Hz.
M4 iPad Pro lacks always-on display despite OLED panel with variable refresh rate (2024):
https://9to5mac.com/2024/05/09/m4-ipad-pro-always-on-display...
this is just regurgitating the manufacturer's claim. I believe it when I see it. Most of display energy use is to turn on the OLED/backlight. They're claiming, because our display flickers less, it's 48% more efficient now.
Is this materially different from panel self refresh?
A low refresh rate probably still requires the same display-side framebuffer as PSR.
With conventional PSR, I think the goal is to power off the link between the system framebuffer and the display controller and potentially power down the system framebuffer and GPU too. This may not be beneficial unless it can be left off long enough, and there may be substantial latency to fire it all back up. You do it around sleep modes where you are expecting a good long pause.
Targeting 1 Hz sounds like actually planning to clock down the link and the system framebuffer so they can run sustain low bandwidth in a more steady state fashion. Presumably you also want to clock down any app and GPU work to not waste time rendering screens nobody will see. This seems just as challenging, i.e. having a "sync to vblank" that can adapt all the way down to 1 Hz?
But why 1hz? Can’t the panel just leave the pixels on the screen for an arbitrary length of time until something triggers refresh? Only a small amount of my screen changes as I’m typing.