From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout4.w1.samsung.com ([210.118.77.14]:39890 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751056AbdEaMEQ (ORCPT ); Wed, 31 May 2017 08:04:16 -0400 Subject: Re: [PATCH] ARM: dts: exynos: Add HDMI CEC device to Exynos5 SoC family To: Hans Verkuil , linux-media@vger.kernel.org, linux-samsung-soc@vger.kernel.org Cc: Krzysztof Kozlowski , Bartlomiej Zolnierkiewicz , Andrzej Hajda From: Marek Szyprowski Message-id: <2497f348-5d66-f10a-5591-c490b7ee8b4e@samsung.com> Date: Wed, 31 May 2017 14:04:00 +0200 MIME-version: 1.0 In-reply-to: <44c9e8c6-669c-848c-30df-eabad6dc1a39@xs4all.nl> Content-type: text/plain; charset=utf-8; format=flowed Content-transfer-encoding: 7bit Content-language: en-US References: <1496228417-31126-1-git-send-email-m.szyprowski@samsung.com> <44c9e8c6-669c-848c-30df-eabad6dc1a39@xs4all.nl> Sender: linux-media-owner@vger.kernel.org List-ID: Hi Hans, On 2017-05-31 13:17, Hans Verkuil wrote: > On 05/31/17 13:00, Marek Szyprowski wrote: >> Exynos5250 and Exynos542x SoCs have the same CEC hardware module as >> Exynos4 SoC series, so enable support for it using the same compatible >> string. >> >> Tested on Odroid XU3 (Exynos5422) and Google Snow (Exynos5250) boards. > Thanks! > > Do you know if the CEC block is always on for these devices or only if there > is a hotplug signal? That was a problem with the exynos4 odroid. Odroid XU3 has exactly same wiring between SoC & HDMI connector (via IP4791CZ12 chip) as Odroid U3, so I expect the same issues. I don't have schematic for Google Snow board, so I have no idea how it works there. > I have made a patch (not posted yet) to signal this in the device tree and > added a CEC capability to signal this to the user. > > This capability will be added to 4.13 (see my patch 'cec: add CEC_CAP_NEEDS_HPD' > from May 25th) since the DisplayPort CEC tunneling feature needs it as well. > > It's easy to test: don't connect an HDMI cable and run: > > cec-ctl --playback > cec-ctl -t0 --image-view-on > > If this returns with a NACK error, then it is OK. If you get a kernel message > that the transmit timed out, then you need this capability since CEC is disabled > without HPD. I've checked those commands, but on all tested boards (Odroid U3+, Odroid XU3 and Google Snow) I get the following message: Transmit from Unregistered to TV (255 to 0): CEC_MSG_IMAGE_VIEW_ON (0x04) Sequence: 19 Tx Timestamp: 175.935s Tx, Error (1), Max Retries I have never got a timeout message from the kernel. Do I need to enable some kind of CEC debugs? > [...] Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland