linux-kernel - Re: [PATCH] drm/vc4: dsi: Only register our component once a DSI device is attached

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

Message-ID: <20210621160517.5fptdj4tkbzgqn76@gilmour>
Date:   Mon, 21 Jun 2021 18:05:17 +0200
From:   Maxime Ripard <maxime@...no.tech>
To:     Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Marek Vasut <marex@...x.de>,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        Eric Anholt <eric@...olt.net>,
        Tim Gover <tim.gover@...pberrypi.com>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        Andrzej Hajda <a.hajda@...sung.com>,
        bcm-kernel-feedback-list@...adcom.com,
        linux-rpi-kernel@...ts.infradead.org,
        Phil Elwell <phil@...pberrypi.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] drm/vc4: dsi: Only register our component once a DSI
 device is attached

Hi Laurent,

On Sun, Jun 20, 2021 at 04:44:33AM +0300, Laurent Pinchart wrote:
> Hi Maxime,
> 
> I'm testing this, and I'm afraid it causes an issue with all the
> I2C-controlled bridges. I'm focussing on the newly merged ti-sn65dsi83
> driver at the moment, but other are affected the same way.
> 
> With this patch, the DSI component is only added when the DSI device is
> attached to the host with mipi_dsi_attach(). In the ti-sn65dsi83 driver,
> this happens in the bridge attach callback, which is called when the
> bridge is attached by a call to drm_bridge_attach() in vc4_dsi_bind().
> This creates a circular dependency, and the DRM/KMS device is never
> created.

We discussed it on IRC, but it makes more sense here.

The thing is, that patch is fixing a circular dependency we discussed
with Andrzej a year ago:

https://lore.kernel.org/dri-devel/20200630132711.ezywhvoiuv3swo57@gilmour.lan/

It seems like we have to choose between having the panels or bridges
working :/

Maxime

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)