2011/11/16 Matthew Garrett <mjg59 at srcf.ucam.org>: > On Wed, Nov 16, 2011 at 06:03:15PM +0100, Michel D?nzer wrote: > >> I thought the main reason for the delay wasn't broken hardware but to >> avoid constantly ping-ponging the vblank IRQ between on and off with >> apps which regularly neeed the vblank counter value, as that could make >> the counter unreliable. Maybe I'm misremembering though. > > If turning it on and off results in the counter value being wrong then > surely that's a hardware problem? I've tested that turning it on and off > between every IRQ still gives valid counter values on sandybridge. This, and the thread that contains it, might be interesting: http://permalink.gmane.org/gmane.comp.video.dri.devel/53201 In summary: there was some resistance to doing this in January, but I couldn't find any legitimate reason. --Andy
