Le Sat, 21 Oct 2006 11:59:14 -0400, Lee Revell <[EMAIL PROTECTED]> a écrit :
> On Fri, 2006-10-20 at 16:53 -0400, Paul Davis wrote: > > On Fri, 2006-10-20 at 22:44 +0200, Tim Goetze wrote: > > > [Fons Adriaensen] > > > >Input the vertical video sync signal via the audio card and analyse > > > >its timing in terms of audio samples (e.g. using a DLL). This will > > > >enable you to predict where the next sync will be in the audio input. > > > > > > Back in the 80s, the humble Commodore 64 could be readily programmed > > > to fire an interrupt on vertical sync. Have 20 years of progress > > > really deprived us of this fine feature, or is it just missing from X? > > > > it was missing from X until Xorg put it back in as an extension. its > > obviously not of much use in a general purpose X app, since the display > > may not be the host on which the app runs, making access to the vsync > > pulse pretty pointless. > > > > I think any Linux system with DRI can do this. Check /proc/interrupts - > if your video card is listed, then you should have vsync interrupt > capability. > > Lee > I have a nvidia card in my box. If I use the nvidia driver, I get it in /proc/interrupts, but if I use the nv driver, the card don't use an IRQ. I am not a gamer, and for me, the nv driver is just better because I can use this IRQ for another hardware and get a better IRQ setup with my rt kernel and that already at the PIC level. If compatibility is a concern, I think at it will be better to use a mechanism provided by X that will exist on every single linux box, as to rely on a hardware mechanism that will not be found on every system. -- Dominique Michel
