[Intel-gfx] [PATCH 2/2] drm/i915/vlv: Replaced Blitter ring based flips with MMIO Flips for VLV.

[Goel, Akash]

Please could you kindly elaborate here, it will help us to proceed further with this patch.

Best Regards
Akash

-----Original Message-----
From: Goel, Akash 
Sent: Monday, January 13, 2014 3:17 PM
To: Chris Wilson
Cc: intel-gfx at lists.freedesktop.org
Subject: RE: [Intel-gfx] [PATCH 2/2] drm/i915/vlv: Replaced Blitter ring based flips with MMIO Flips for VLV.

>> Rather exporting deep magic from i915_gem, just emit the request after the mmio flip and use the normal signalling mechanisms. There are other users who could also use a request after a flip.

Sorry, couldn't understand your point.

With Command streamer based flips, we could use the cross ring MBOX mechanism at Hw level, to ensure that buffer is flipped only when the rendering is completed. 

But with MMIO flips, need to ensure that we somehow introduce a wait for the rendering to complete, before updating the Display Surface Address register, to effect the flip. 

Best Regards
Akash

-----Original Message-----
From: Chris Wilson [mailto:chris at chris-wilson.co.uk]
Sent: Thursday, January 09, 2014 5:02 PM
To: Goel, Akash
Cc: intel-gfx at lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH 2/2] drm/i915/vlv: Replaced Blitter ring based flips with MMIO Flips for VLV.

On Thu, Jan 09, 2014 at 04:56:39PM +0530, akash.goel at intel.com wrote:
> From: Akash Goel <akash.goel at intel.com>
> 
> Using MMIO based flips now on VLV for Media power well residency optimization.
> The blitter ring is currently being used just for the command streamer 
> based flip calls. For pure 3D workloads, with MMIO flips, there will 
> be no use of blitter ring and this will ensure the 100% residency in D0i3 for Media well.
> The other alternative of having Render ring based flip calls is not 
> being used, as that option adversly affects the performance (FPS) of 
> certain 3D Apps

Rather exporting deep magic from i915_gem, just emit the request after the mmio flip and use the normal signalling mechanisms. There are other users who could also use a request after a flip.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre