Re: [PATCH 3/3] drm/i915: Use vblank evade mechanism in mmio_flip

From: Damien Lespiau <damien.lespiau@intel.com>
To: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Cc: intel-gfx@lists.freedesktop.org, ville.syrjala@intel.com,
	shuang.he@linux.intel.com, paulo.zanoni@intel.com
Subject: Re: [PATCH 3/3] drm/i915: Use vblank evade mechanism in mmio_flip
Date: Tue, 28 Oct 2014 14:18:01 +0000	[thread overview]
Message-ID: <20141028141801.GA29136@strange.ger.corp.intel.com> (raw)
In-Reply-To: <1414501814-1465-3-git-send-email-ander.conselvan.de.oliveira@intel.com>

On Tue, Oct 28, 2014 at 03:10:14PM +0200, Ander Conselvan de Oliveira wrote:
> Currently we program just DPSCNTR and DSPSTRIDE directly from the ring
> interrupt handler, which is fine since the hardware guarantees that
> those are update atomically. When we have atomic page flips we'll want
> to be able to update also the offset registers, and then we need to use
> the vblank evade mechanism to guarantee atomicity. Since that mechanism
> introduces a wait, we need to do the actual register write from a work
> when it is triggered by the ring interrupt.
> 
> v2: Explain the need for mmio_flip.work in the commit message (Paulo)
>     Initialize the mmio_flip work in intel_crtc_init() (Paulo)
>     Prevent new flips the previous flip work finishes (Paulo)
>     Don't acquire modeset locks for mmio flip work

So that means you can replace the content of intel_do_mmio() by a call
to dev_priv->display.update_primary_plane() on top of this patch? That'd
do the right thing on SKL, which would make me happy.

-- 
Damien
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