linux-kernel - Re: [PATCH] drm: Add "min bpc" connector property

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Message-ID: <f1abafa2-97e8-49ad-abc8-c71914ac2212@mailbox.org>
Date: Mon, 3 Nov 2025 12:22:55 +0100
From: Michel Dänzer <michel.daenzer@...lbox.org>
To: Sasha McIntosh <sashamcintosh@...gle.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>
Cc: David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 trivial@...nel.org
Subject: Re: [PATCH] drm: Add "min bpc" connector property

On 10/31/25 21:45, Sasha McIntosh wrote:
> [Why]
> When playing HDR or WCG content, bandwidth constraints may force the
> driver to downgrade to 6bpc, resulting in visual artifacts like banding.
> 
> Userspace should be able to configure a minimum allowed bpc.
> 
> [How]
> Introduce the "min bpc" connector property so the user can limit the
> minimum bpc. Mirror the "mac bpc" implementation.

One issue with this is that the effective bpc of the link (as observed by the user) can be higher than the physical bpc, due to things like DSC or various dithering techniques. So requiring a minimum physical bpc could artificially exclude configurations which would otherwise work fine.


-- 
Earthling Michel Dänzer       \        GNOME / Xwayland / Mesa developer
https://redhat.com             \               Libre software enthusiast