[Intel-gfx] [PATCH 3/6] drm/i915: reset eDP timestamps on resume

[Chris Wilson]

On Fri, Jan 17, 2014 at 06:17:42PM -0200, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> The eDP code records a few timestamps containing the last time we took
> some actions, because we need to wait before doing some other actions.
> The problem is that if we store a timestamp when suspending and then
> look at it when resuming, we'll ignore the unknown amount of time we
> actually were suspended.
> 
> This happens with the panel power cycle delay: it's 500ms on my
> machine, and it's delaying the resume sequence by 200ms due to a
> timestamp we recorded before suspending. This patch should solve this
> problem by resetting the timestamps.

But you don't explain why this is safe. The code nerfs the timeouts so
that they are ignored, yet the delays are independent. Should this be
based on realtime rather than jiffies?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre