[mythtv] Potential new vsync method for NVidia cards
Mike Wright
bodyjarrocks at gmail.com
Sun Apr 17 04:11:21 UTC 2005
Hi all,
I just came across this code from the DirectFB project:
static DFBResult
nvcrtc1WaitVSync( CoreScreen *screen,
void *driver_data,
void *screen_data )
{
NVidiaDriverData *nvdrv = (NVidiaDriverData*) driver_data;
volatile __u8 *PCIO = nvdrv->PCIO;
if (!dfb_config->pollvsync_none) {
while ( nv_in8( PCIO, 0x3DA ) & 8 );
while (!(nv_in8( PCIO, 0x3DA ) & 8));
// using PCRTC
//while ( nv_in32( nvdrv->PCRTC, 0x808 ) & 0x10000 );
//while (!(nv_in32( nvdrv->PCRTC, 0x808 ) & 0x10000));
}
return DFB_OK;
}
To me it looks like this is some code which figures out when the VSync
occurs on an NVidia card. Why would you care? Well last time I
looked (and that was a while ago) the only way of tracking vsync on
Nvidia was via the OpenGL method. That means you have to use
NVidia's drivers - which a lot of people find cause system
instability. If someone could figure out how to un-DirectFBize
this code then theoretically you could use the open-source NV X
driver (which I find to be rock solid) and NVTV to control TV-out.
Just a thought . . . If this is old news then my apologies.
Cheers,
Mike.
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