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From: Daniel Stone <daniel@fooishbar.org>
To: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Sebastian Reichel <sebastian.reichel@collabora.co.uk>,
	Sebastian Reichel <sre@kernel.org>,
	Tony Lindgren <tony@atomide.com>, Pavel Machek <pavel@ucw.cz>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	devicetree@vger.kernel.org, linux-omap@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	kernel@collabora.com
Subject: Re: [PATCHv3 3/8] drm/omap: add support for manually updated displays
Date: Fri, 20 Apr 2018 11:19:35 +0100	[thread overview]
Message-ID: <CAPj87rPeBim9NyBmMuDKKEwx2apLhdnZyEB9_sfbVQpUHA95+Q@mail.gmail.com> (raw)
In-Reply-To: <a078d8c3-9e65-cc7b-737a-cbd5cf141f95@ti.com>

Hi Tomi,

On 20 April 2018 at 08:09, Tomi Valkeinen <tomi.valkeinen@ti.com> wrote:
> It's actually not quite clear to me how manual update displays work with
> DRM...
>
> As far as I see, we have essentially two cases: 1) single buffering,
> where the userspace must set an area in the fb dirty, which then
> triggers the update, 2) multi buffering, which doesn't need fb dirty,
> but just a page flip which triggers the update.
>
> In the 2) case (which I think is the optimal case which all the modern
> apps should use), there's no need for delayed work or any work, and the
> code flow should be very similar to the auto-update model.

Correct. There's been talk (and I think patches?) of adding a
per-plane dirty property, so userspace can as an optimisation inform
the kernel of the area changed between frames. But short of that, a
pageflip needs to trigger a full-plane update, with no dirtyfb
required.

Cheers,
Daniel

  parent reply	other threads:[~2018-04-20 10:19 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-30 17:18 [PATCHv3 0/8] omapdrm: DSI command mode panel support Sebastian Reichel
2018-03-30 17:18 ` [PATCHv3 1/8] drm/omap: add framedone interrupt support Sebastian Reichel
2018-03-30 17:18 ` [PATCHv3 2/8] drm/omap: add manual update detection helper Sebastian Reichel
2018-03-30 17:18 ` [PATCHv3 3/8] drm/omap: add support for manually updated displays Sebastian Reichel
2018-04-20  7:09   ` Tomi Valkeinen
2018-04-20  8:11     ` Daniel Vetter
2018-04-20 10:19     ` Daniel Stone [this message]
2018-04-20 14:25       ` Tony Lindgren
2018-04-20 14:39         ` Daniel Stone
2018-04-20 14:44           ` Tony Lindgren
2018-03-30 17:18 ` [PATCHv3 4/8] drm/omap: make omap_framebuffer_get_next_connector static Sebastian Reichel
2018-03-30 17:18 ` [PATCHv3 5/8] dt-bindings: panel: common: document orientation property Sebastian Reichel
2018-04-03 10:49   ` Pavel Machek
2018-04-09 20:29   ` Rob Herring
2018-03-30 17:18 ` [PATCHv3 6/8] drm/omap: add support for rotation hints from display drivers Sebastian Reichel
2018-03-30 17:18 ` [PATCHv3 7/8] drm/omap: panel-dsi-cm: add rotation support Sebastian Reichel
2018-04-03 10:49   ` Pavel Machek
2018-03-30 17:18 ` [PATCHv3 8/8] ARM: dts: omap4-droid4: Add LCD panel rotation property Sebastian Reichel
2018-04-03 10:49   ` Pavel Machek

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