From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1AAAC47095 for ; Mon, 7 Jun 2021 11:56:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B25A4611AD for ; Mon, 7 Jun 2021 11:56:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230294AbhFGL6U (ORCPT ); Mon, 7 Jun 2021 07:58:20 -0400 Received: from ni.piap.pl ([195.187.100.5]:55290 "EHLO ni.piap.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230177AbhFGL6T (ORCPT ); Mon, 7 Jun 2021 07:58:19 -0400 Received: from t19.piap.pl (OSB1819.piap.pl [10.0.9.19]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ni.piap.pl (Postfix) with ESMTPSA id E3B25444267; Mon, 7 Jun 2021 13:56:25 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 ni.piap.pl E3B25444267 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=piap.pl; s=mail; t=1623066985; bh=RThC5tsnWT+d2Y9LB+HdF4WLkbKitBQLeYlAH9yKOcs=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=Aybt25zqljokccbujawefkQKfJ6iY4bViRwqLV0EYtQzSC4SWv8+3ebzw61WC+OBu nU5qtWc1SoBf7pLChw7+dPWqzh+maORn3bj0vuGYRLQ/1NvuFFdYH2oSxJJHStsz50 ZSUcPZg7lQIazxTP7HDQUEyUZGfXIpi1cgk4hqD0= From: =?utf-8?Q?Krzysztof_Ha=C5=82asa?= To: Hans Verkuil Cc: Tim Harvey , Mauro Carvalho Chehab , linux-media@vger.kernel.org, lkml Subject: Re: [PATCH] TDA1997x: enable EDID support References: Sender: khalasa@piap.pl Date: Mon, 07 Jun 2021 13:56:25 +0200 In-Reply-To: (Hans Verkuil's message of "Mon, 7 Jun 2021 13:11:54 +0200") Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-KLMS-Rule-ID: 4 X-KLMS-Message-Action: skipped X-KLMS-AntiSpam-Status: not scanned, whitelist X-KLMS-AntiPhishing: not scanned, whitelist X-KLMS-AntiVirus: Kaspersky Security for Linux Mail Server, version 8.0.3.30, not scanned, whitelist Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Hans, Hans Verkuil writes: >> Without this patch, the TDA19971 chip's EDID is inactive. > > Was this wrong from the very beginning? How can this ever have been tested > without an EDID? It seems so. I suspect it might have worked in tests because this register isn't cleared on reboot. I.e., setting it once after power up makes it work to the next power up. Or, maybe, the HDMI signal source didn't need EDID. I'm looking at the previous version of this driver from Gateworks and it contains: /* Configure EDID * * EDID_ENABLE bits: * 7 - nack_off * 6 - edid_only * 1 - edid_b_en * 0 - edid_a_en */ reg =3D io_read(REG_EDID_ENABLE); if (!tda1997x->internal_edid) reg &=3D ~0x83; /* EDID Nack ON */ else reg |=3D 0x83; /* EDID Nack OFF */ io_write(REG_EDID_ENABLE, reg); Not sure what the "non-internal" EDID could be - a separate I2C EEPROM chip? I'm using this on Gateworks' GW54xx boards and I can't see any such EEPROM in the vicinity of the TDA19971, but I don't know how it is wired - perhaps Tim has some idea? --=20 Krzysztof Ha=C5=82asa Sie=C4=87 Badawcza =C5=81ukasiewicz Przemys=C5=82owy Instytut Automatyki i Pomiar=C3=B3w PIAP Al. Jerozolimskie 202, 02-486 Warszawa