linux-kernel - Re: [RFC PATCH v2] media: cec: expose HDMI connector to CEC dev mapping

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Date:   Thu, 16 May 2019 16:21:58 +0200
From:   Hans Verkuil <hverkuil@...all.nl>
To:     Dariusz Marcinkiewicz <darekm@...gle.com>
Cc:     linux-media@...r.kernel.org, hans.verkuil@...co.com,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v2] media: cec: expose HDMI connector to CEC dev
 mapping

On 5/16/19 4:10 PM, Dariusz Marcinkiewicz wrote:
> Hi Hans.
> 
> From: Hans Verkuil <hverkuil@...all.nl>
> Date: Thu, May 9, 2019 at 11:31 AM
> To: Dariusz Marcinkiewicz
> Cc: <linux-media@...r.kernel.org>, <hans.verkuil@...co.com>,
> <linux-kernel@...r.kernel.org>
> 
>> On 5/9/19 9:52 AM, Dariusz Marcinkiewicz wrote:
>>> Hi Hans.
>>>
>>> On Wed, Apr 24, 2019 at 2:09 PM Hans Verkuil <hverkuil@...all.nl> wrote:
>>>>
>>>> Hi Dariusz,
>>>>
>>>> This is getting close, so I think for the next version you can drop
>>>> the RFC tag.
>>>>
>>>> Some comments:
>>>>
>>> ...
>>>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-cec.c
>>>>> @@ -261,7 +261,7 @@ static int dw_hdmi_cec_probe(struct platform_device *pdev)
>>>>>       cec->adap = cec_allocate_adapter(&dw_hdmi_cec_ops, cec, "dw_hdmi",
>>>>>                                        CEC_CAP_LOG_ADDRS | CEC_CAP_TRANSMIT |
>>>>>                                        CEC_CAP_RC | CEC_CAP_PASSTHROUGH,
>>>>> -                                      CEC_MAX_LOG_ADDRS);
>>>>> +                                      CEC_MAX_LOG_ADDRS, NULL);
>>>>
>>>> Hmm, the connector information is actually available through cec->hdmi.
>>>>
>>>> I think it would make sense to create a helper function that fills in
>>>> struct cec_connector_info based on a struct drm_connector pointer.
>>>> And add a function to drivers/gpu/drm/bridge/synopsys/dw-hdmi.c that
>>>> dw-hdmi-cec.c can call that does the same.
>>>
>>> Looking at the code here, is the connector info guaranteed to be
>>> available at the time cec_allocate_adapter is called here?
>>> drm_connector won't be initialized until dw_hdmi_bridge_attach is
>>> called, which happens after the cec platform device is created.
>>
>> Good point. The creation of the cec platform device should probably
>> be moved to dw_hdmi_bridge_attach.
>>
>>> ...
>>>>>       priv->adap = cec_allocate_adapter(&tda9950_cec_ops, priv, "tda9950",
>>>>>                                         CEC_CAP_DEFAULTS,
>>>>> -                                       CEC_MAX_LOG_ADDRS);
>>>>> +                                       CEC_MAX_LOG_ADDRS,
>>>>> +                                       NULL);
>>>>
>>>> Here too the drm_connector can be found via struct tda9950_glue.
>>>> So it is easy to provide proper connector information.
>>>
>>> The same concern as with the comment before.
>>
>> Same solution: this has to be moved.
>>
>> I have hardware to test patches for both drivers. It might take 2-3 weeks
>> before I can test as I don't always has access to the hardware, but at
>> least I can verify that moving this code won't break anything.
>>
>> It's best to first move the code in separate patches before applying the
>> "expose HDMI connector to CEC dev mapping" patch on top of them.
>>
> 
> I've submitted another revision of the changes, with those 2 patches
> added on top. Hope that is ok.
> 
> Please take a look. It would be great if you could give those 2
> patches a go on an actual hardware.

I should be able to test the dw-hdmi patch next week, but testing the tda9950 patch
has to wait until the week after that.

Regards,

	Hans

> 
> Thank you and best regards.
>