Hi Timothy, It starts counting at system startup/boot and just keeps going. That's how linux' struct fb_vblank describes it, so I don't think it makes sense to have different semantics in DirectFB for this - other systems/screen drivers implementing it should do exactly the same I think.
And yes, it will wrap around at some point - but you'll have this with any counter - 32bits is still a long time for vsyncs... Also, I think maybe the counter should be changed to u32? Again, that's how the kernel defines it for the fbdev system, instead of unsigned long. I noticed only now :-( Cheers, Andre' On Fri, 2010-01-29 at 09:29 -0800, Strelchun, Timothy wrote: > Hi Andre', > > What's your definition for current vertical sync count? > > I assume it starts incrementing when the current output display mode was > configured by the display drivers or DFB. Thus it is reset to zero each time > the current output display mode is reconfigured by the display drivers or > DFB. I also assume it will simply wrap on overflow (only way to determine is > tracking the previous value). > > This is important to understand for other system drivers that will require > different implementations of IDirectFBScreen::GetVSyncCount. > > Thanks, > Timothy > > -- > > Timothy Strelchun > CE Software Engineering > Digital Home Group > Intel Corporation > > The views expressed above are my own and not those of Intel > > >-----Original Message----- > >From: directfb-dev-boun...@directfb.org > >[mailto:directfb-dev-boun...@directfb.org] On Behalf Of Andre DRASZIK > >Sent: Friday, January 29, 2010 4:01 AM > >To: directfb-dev > >Subject: [directfb-dev] screen related patches > > > >Hi, > > > >attached are two patches - > > > >1) fixes incorrect patching of the frequency for NTSC/PAL-60 > >standards (they are defined as 59.94Hz not 60Hz, this is simply wrong) > > > >2) I would like to have an API to retrieve the current VSync > >count - attached is an implementation for the fbdev system. > > > > > >Cheers, > >Andre' > > > > > _______________________________________________ > directfb-dev mailing list > directfb-dev@directfb.org > http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev _______________________________________________ directfb-dev mailing list directfb-dev@directfb.org http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev
