Re: [Intel-gfx] [PATCH] drm: Aggressively disable vblanks

On Mon, 20 Dec 2010 14:00:54 -0500, Andy Lutomirski luto@MIT.EDU wrote:

Enabling and disabling the vblank interrupt (on devices that support it) is cheap. So disable it quickly after each interrupt.

So, the concern (and reason for the original design) was that you might lose count of vblank interrupts as vblanks are counted differently while off than while on. If vblank interrupts get enabled near the interrupt time, is it possible that you'll end up off by one somehow?

Leaving them enabled for 'a while' was supposed to reduce the impact of this potential error.