From: Hans Verkuil <hverkuil@xs4all.nl>
To: Dariusz Marcinkiewicz <darekm@google.com>
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 1/3] media: cec: expose HDMI connector to CEC dev mapping
Date: Wed, 29 May 2019 16:47:42 +0200 [thread overview]
Message-ID: <a421ff13-c8ee-b72c-3e1e-376b9e426064@xs4all.nl> (raw)
In-Reply-To: <8e575d0b-4765-ae54-019e-0fab522fe1d5@xs4all.nl>
On 5/28/19 10:05 AM, Hans Verkuil wrote:
> On 5/28/19 9:53 AM, Dariusz Marcinkiewicz wrote:
>> On Fri, May 24, 2019 at 11:21 AM Hans Verkuil <hverkuil@xs4all.nl> wrote:
>>>
>>> Hi Dariusz,
>>>
>>> I did some more testing with the Khadas VIM2 and found another problem,
>>> something that will, unfortunately, require some redesign.
>>>
>> ...
>>>
>>> The other problem is in the CEC driver: it creates the CEC device as
>>> soon as the HDMI device is found (cec_notifier_parse_hdmi_phandle).
>>>
>>> But that doesn't mean that the HDMI device also had registered itself
>>> as a CEC notifier.
>>>
>>> Until now that never mattered: as long as the HDMI device was found
>>> the CEC adapter would function fine, it would just have no physical
>>> address until so notified by the HDMI device once it registered its
>>> CEC notifier.
>>>
>>> But if we want to have valid connector info during the lifetime of
>>> the CEC adapter, then this no longer works.
>>>
>>> I'm not entirely sure how to handle this.
>>>
>>> Another issue here is that when the HDMI driver removes the notifier,
>>> then it should also zero the connector info. Remember that both the
>>> HDMI and the CEC drivers can be loaded and unloaded independently from
>>> one another.
>>>
>> Given all of the above, what do you think about coming back to the v1
>> of the patch, where a connector info could be set on an adapter at any
>> time and an event was used to notify userland when that happened? That
>> approach seems to cover all the scenarios mentioned above.
>
> That's just hiding the real problems :-)
>
> I hope to spend some time on CEC tomorrow and I'll get back to you then.
Unfortunately I had too many other things going on to spend time on this.
Hopefully next week.
Regards,
Hans
next prev parent reply other threads:[~2019-05-29 14:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-21 10:52 [PATCH v7 1/3] media: cec: expose HDMI connector to CEC dev mapping Dariusz Marcinkiewicz
2019-05-21 10:52 ` [PATCH v7 2/3] drm/bridge: dw-hdmi: pass connector info to the CEC adapter Dariusz Marcinkiewicz
2019-05-21 10:52 ` [PATCH v7 3/3] drm/i2c: tda9950: pass HDMI connector info to " Dariusz Marcinkiewicz
2019-05-24 9:21 ` [PATCH v7 1/3] media: cec: expose HDMI connector to CEC dev mapping Hans Verkuil
2019-05-28 7:53 ` Dariusz Marcinkiewicz
2019-05-28 8:05 ` Hans Verkuil
2019-05-29 14:47 ` Hans Verkuil [this message]
2019-06-19 11:05 ` Dariusz Marcinkiewicz
2019-06-19 11:26 ` Hans Verkuil
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