From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keith Packard <keithp@keithp.com>
Subject: Re: [PATCH] drm: Aggressively disable vblanks
Date: Mon, 20 Dec 2010 19:23:40 -0800
Message-ID: <yunfwtrrepv.fsf@aiko.keithp.com>
References: <372cb262d2d49bd796fa6636d04d431b50a14f69.1292869603.git.luto@mit.edu>
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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.

=2D-=20
keith.packard@intel.com

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