From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
To: CK Hu <ck.hu@mediatek.com>, dri-devel@lists.freedesktop.org
Cc: chunkuang.hu@kernel.org, airlied@linux.ie,
linux-kernel@vger.kernel.org, andrzej.hajda@intel.com,
linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com,
kernel@collabora.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge
Date: Tue, 11 Jan 2022 12:05:56 +0100 [thread overview]
Message-ID: <8a87c97e-fd58-bc73-44a6-0055b86cd7ea@collabora.com> (raw)
In-Reply-To: <c0279078032bae61e6c1d70be74d1fb8c528083f.camel@mediatek.com>
Il 06/01/22 06:22, CK Hu ha scritto:
> Hi, Angelo:
>
> On Tue, 2022-01-04 at 10:59 +0100, AngeloGioacchino Del Regno wrote:
>> DRM bridge drivers are now attaching their DSI device at probe time,
>> which requires us to register our DSI host in order to let the bridge
>> to probe: this recently started producing an endless -EPROBE_DEFER
>> loop on some machines that are using external bridges, like the
>> parade-ps8640, found on the ACER Chromebook R13.
>>
>> Now that the DSI hosts/devices probe sequence is documented, we can
>> do adjustments to the mtk_dsi driver as to both fix now and make sure
>> to avoid this situation in the future: for this, following what is
>> documented in drm_bridge.c, move the mtk_dsi component_add() to the
>> mtk_dsi_ops.attach callback and delete it in the detach callback;
>> keeping in mind that we are registering a drm_bridge for our DSI,
>> which is only used/attached if the DSI Host is bound, it wouldn't
>> make sense to keep adding our bridge at probe time (as it would
>> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
>> that one to the dsi host attach function (and remove it in detach).
>
> This patch looks good to me, but please add 'Fixes' tag to note to
> which patch this patch want to fix.
>
> Regards,
> CK
>
Hello,
unfortunately I couldn't find a valid commit for a Fixes tag. This
started being an issue at some point, when the DRM API was changed to
adhere to the documented probe sequence: the MediaTek DSI driver was
not the only one that got broken/affected by these changes.
If you have any advice on which commit should be tagged, I'm open for
any kind of suggestion.
Thanks,
- Angelo
next prev parent reply other threads:[~2022-01-11 11:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-04 9:59 [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge AngeloGioacchino Del Regno
2022-01-06 5:22 ` CK Hu
2022-01-11 11:05 ` AngeloGioacchino Del Regno [this message]
2022-01-12 7:09 ` Jagan Teki
2022-01-27 10:32 ` AngeloGioacchino Del Regno
2022-01-27 14:21 ` Chun-Kuang Hu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8a87c97e-fd58-bc73-44a6-0055b86cd7ea@collabora.com \
--to=angelogioacchino.delregno@collabora.com \
--cc=airlied@linux.ie \
--cc=andrzej.hajda@intel.com \
--cc=chunkuang.hu@kernel.org \
--cc=ck.hu@mediatek.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=kernel@collabora.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=matthias.bgg@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).