On Wed, Oct 21, 2020 at 4:59 PM Ken Huang <kenbshuang@xxxxxxxxxx> wrote: > > Hi All, > > It's useful in Android and other embedded devices to implement Always On Display (ex. showing clock faces with less than 15% OPR on screen). > > OPR (On Pixel Ratio) is the percentage of luminance amount over the display area. > It's derived by gray levels of display image pattern and the backlight (or OLED) driving force (or current). > ex: OPR=100% means a full white pattern with maximum backlight (or OLED) brightness, while full black would be OPR=0%. > > In userspace, when the client initializes, we can set capability via drmSetClientCap() to ask the display driver to expose the drm modes with DRM_MODE_FLAG_LOW_POWER flag. > Userspace can check DRM_MODE_FLAG_LOW_POWER flag to know which modes can be used to consume the least amount of power during Always On Display. > Ignoring modes with this flag set during normal operating mode. Hm I'm not really sure what this changes ... I think we need the entire pile of patches: Userspace, driver, drm core, anything else. Just adding this flag doesn't make much sense really, since I have no idea what the semantics are. Even after you've explained the use-case. Also for new kms uapi we need an igt testcase to exercise this and make sure it works. -Daniel > > Thanks, > Ken > > Daniel Vetter <daniel@xxxxxxxx> 於 2020年10月21日 週三 下午4:34寫道： >> >> On Wed, Oct 21, 2020 at 07:40:48AM +0000, Simon Ser wrote: >> > On Wednesday, October 21, 2020 8:54 AM, Ken Huang <kenbshuang@xxxxxxxxxx> wrote: >> > >> > > From: Adrian Salido salidoa@xxxxxxxxxx >> > > >> > > Some displays may support Low Power modes, however, these modes may >> > > require special handling as they would usually require lower OPR >> > > content on framebuffers. >> > >> > I'm not familiar with OPR. Can you explain what it is and what it means >> > for user-space? >> >> Also since this is new uapi, I guess best explanation would include the >> userspace code that makes sensible use of this. >> -Daniel >> -- >> Daniel Vetter >> Software Engineer, Intel Corporation >> http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
