linux-kernel - Re: [PATCH v2] drm/bridge-connector: Prioritize supported_formats over ycbcr_420

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <d983544b-fbfb-41ed-8af0-31b92e2f904b@collabora.com>
Date: Tue, 17 Dec 2024 01:47:54 +0200
From: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Andrzej Hajda <andrzej.hajda@...el.com>,
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 kernel@...labora.com, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/bridge-connector: Prioritize supported_formats
 over ycbcr_420_allowed

On 12/17/24 1:32 AM, Dmitry Baryshkov wrote:
> On Tue, Dec 17, 2024 at 01:17:48AM +0200, Cristian Ciocaltea wrote:
>> Hi Dmitry,
>>
>> On 12/10/24 3:12 AM, Dmitry Baryshkov wrote:
>>> On Fri, Dec 06, 2024 at 10:00:46PM +0200, Cristian Ciocaltea wrote:
>>>> Bridges having the DRM_BRIDGE_OP_HDMI flag set in drm_bridge->ops are
>>>> supposed to rely on drm_bridge->supported_formats bitmask to advertise
>>>> the supported colorspaces, including HDMI_COLORSPACE_YUV420.  Therefore,
>>>> the newly introduced drm_bridge->ycbcr_420_allowed flag becomes
>>>> redundant in this particular context.
>>>>
>>>> Moreover, when drm_bridge_connector gets initialised, only
>>>> drm_bridge->ycbcr_420_allowed is considered in the process of adjusting
>>>> the equivalent property of the base drm_connector, which effectively
>>>> discards the formats advertised by the HDMI bridge.
>>>
>>> I think this should be handled in a different way: during HDMI connector
>>> init verify that HDMI_COLORSPACE_YUV420 matches the
>>> drm_connector->ycbcr_420_allowed value and rejects incompatible
>>> connectors.
>>
>> I added a 2nd patch in v3 [1] to perform this verification on HDMI
>> connector init, but I think we still need a proper handling of the
>> inconsistency at bridge[-connector] level. I simplified a bit the initial
>> approach, hopefully that would bring us closer to an acceptable solution.
> 
> I'm sorry, I first commented on the new patchseries. I think that the
> second patch is enough.

No worries, thanks for your quick review!  Let's move the discussion on
the new series!