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: Tue, 28 May 2019 10:05:47 +0200 [thread overview]
Message-ID: <8e575d0b-4765-ae54-019e-0fab522fe1d5@xs4all.nl> (raw)
In-Reply-To: <CALFZZQH7-mzRZbji1w-UwRLdw6c8+CThn0e96oG8E2Eq1ivANQ@mail.gmail.com>
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.
Regards,
Hans
next prev parent reply other threads:[~2019-05-28 8:05 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 [this message]
2019-05-29 14:47 ` Hans Verkuil
2019-06-19 11:05 ` Dariusz Marcinkiewicz
2019-06-19 11:26 ` Hans Verkuil
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