Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v7 1/3] media: cec: expose HDMI connector to CEC dev
 mapping
To:     Dariusz Marcinkiewicz <darekm@google.com>
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20190521105203.154043-1-darekm@google.com>
 <16889839-b4e9-9984-2e36-5f07ceb7d7f2@xs4all.nl>
 <CALFZZQEao3vqVxKO-3mT5ATtC=ZWO+bc3dA_Xo-mgpqmna_fMQ@mail.gmail.com>
From:   Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <4566a4db-86db-c9ee-3a5b-9e7c605a6da7@xs4all.nl>
Date:   Wed, 19 Jun 2019 13:26:55 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.6.1
MIME-Version: 1.0
In-Reply-To: <CALFZZQEao3vqVxKO-3mT5ATtC=ZWO+bc3dA_Xo-mgpqmna_fMQ@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 6/19/19 1:05 PM, Dariusz Marcinkiewicz wrote:
> Hi Hans.
> 
> I would like to come back to this thread.
> 
> 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.
>>
>> See my comments below...
>>
> ...
>>
>> 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.
>>
> 
> I took a peek at the changes in
> https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=cec-conn. Do I
> understand it correctly, that the above problem is addressed there by
> unregistering an adapter in cec_notifier_conn_unregister (which will
> result in /dev/cecX node going away)? I wonder to what degree this
> solves the problem of HDMI and CEC drivers being loaded and unloaded
> independently. It seems that in cases where HDMI driver is unloaded
> and then loaded again, counterintuitively, the /dev/cecX might not
> come back again, is this right, or am I missing something? Also, is it
> guaranteed that adapter drivers won't try to access an adapter once it
> gets removed by cec_notifier_conn_unregister?

It's old code, I'm going to do it differently (closer to your version,
actually).

I just pushed my latest code, I'm much happier with it.

I'll try to post a patch series this week.

Regards,

	Hans