linux-kernel - Re: [PATCH 0/3] drm: zynqmp: Make the video plane primary

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Message-ID: <aUkPg_VUxp0KrpWE@nuoska>
Date: Mon, 22 Dec 2025 11:29:39 +0200
From: Mikko Rapeli <mikko.rapeli@...aro.org>
To: Sean Anderson <sean.anderson@...ux.dev>
Cc: Thomas Zimmermann <tzimmermann@...e.de>,
	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	Mike Looijmans <mike.looijmans@...ic.nl>,
	David Airlie <airlied@...il.com>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Anatoliy Klymenko <anatoliy.klymenko@....com>,
	Maxime Ripard <mripard@...nel.org>,
	linux-arm-kernel@...ts.infradead.org,
	Simona Vetter <simona@...ll.ch>,
	Michal Simek <michal.simek@....com>
Subject: Re: [PATCH 0/3] drm: zynqmp: Make the video plane primary

Hi,

On Fri, Nov 14, 2025 at 10:35:10AM -0500, Sean Anderson wrote:
> On 11/14/25 02:42, Thomas Zimmermann wrote:
> > Am 13.11.25 um 21:37 schrieb Sean Anderson:
> >> The graphics plane does not support XRGB8888, which is the default mode
> >> X uses for 24-bit color. Because of this, X must be set to use 16-bit
> >> color, which has a measurable performance penalty. Make the video plane
> >> the primary plane as it natively supports XRGB8888. An alternative
> >> approach to add XRGB8888 to the graphics plane is discussed in [1], as
> >> well as in patch 2.
> > 
> > Did you try to set drm_device.mode_config.preferred_depth = 16, like at [1]?  IIRC user space looks at this value to auto-detect the color format.
> 
> I have not tried that. But I would rather use 24-bit color for the performance boost.

I have tested preferred_depth = 16 and it works. Proposed in
https://lists.freedesktop.org/archives/dri-devel/2025-December/540189.html
but I'm also fine with 24/32 bpp, or any default which draws pixels to HDMI
on AMD KV260 and X11 without manually changing the config.

This full series also works for me on AMD KV260 running Yocto genericarm64
machine config and core-image-sato image with Xorg.

Cheers,

-Mikko