linux-kernel - Re: [PATCH 9/9] media: dwc: dw-hdmi-rx: Add support for CEC

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5ef03a9b-01b0-5401-9db1-65c5e9b24cea@xs4all.nl>
Date:   Wed, 2 Jun 2021 20:27:46 +0200
From:   Hans Verkuil <hverkuil-cisco@...all.nl>
To:     Nelson Costa <Nelson.Costa@...opsys.com>,
        "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Jose Abreu <Jose.Abreu@...opsys.com>
Subject: Re: [PATCH 9/9] media: dwc: dw-hdmi-rx: Add support for CEC

On 02/06/2021 20:20, Nelson Costa wrote:
> Hi Hans,
> 
> Thanks for your comments and feedback!
> 
> From: Hans Verkuil <hverkuil-cisco@...all.nl>
> Date: qua, jun 02, 2021 at 13:45:45
> 
>> On 02/06/2021 13:24, Nelson Costa wrote:
>>> @@ -3194,10 +3428,29 @@ static int dw_hdmi_rx_probe(struct platform_device *pdev)
>>>  	if (ret)
>>>  		goto err_phy_exit;
>>>  
>>> +	/* CEC */
>>> +#if IS_ENABLED(CONFIG_VIDEO_DWC_HDMI_RX_CEC)
>>> +	dw_dev->cec_adap = cec_allocate_adapter(&dw_hdmi_cec_adap_ops,
>>> +						dw_dev, dev_name(dev),
>>> +						(CEC_CAP_DEFAULTS |
>>> +						 CEC_CAP_NEEDS_HPD |
>>
>> This cap makes no sense for a receiver.
>>
> 
> This cap was added in order to overcome a scenario that we have when 
> there
> was an hot plug. The driver performs a main reset that cause the loss of
> cec controller configuration. And in that case in order to reconfigure 

What do you mean with 'there was an hot plug'? Are you talking about the HPD
signal? Or when a new source/cable is connected? Can you point to the code
where that happens in the driver?

Regards,

	Hans

> the
> cec this cap was added. Because whenever there is a reset the physical
> address is reconfigured (invalidated and set) and with this cap the cec
> configuration callback function (adap_enable) is called again allowing to
> reconfigure the cec.
> 
> Does it make sense?
> 
> If not, what should be the best approach in order to deal with this 
> scenario?