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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64DEBC6FD1D for ; Thu, 23 Mar 2023 12:27:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231716AbjCWM1P (ORCPT ); Thu, 23 Mar 2023 08:27:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231527AbjCWM1G (ORCPT ); Thu, 23 Mar 2023 08:27:06 -0400 Received: from fllv0015.ext.ti.com (fllv0015.ext.ti.com [198.47.19.141]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CACE53C23; Thu, 23 Mar 2023 05:27:03 -0700 (PDT) Received: from lelv0266.itg.ti.com ([10.180.67.225]) by fllv0015.ext.ti.com (8.15.2/8.15.2) with ESMTP id 32NCQUZh104782; Thu, 23 Mar 2023 07:26:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1679574390; bh=aKqINq5Ot9zplt5xAt4YKK+ybHwjeTQa8lKUsA3qixk=; h=Date:Subject:To:CC:References:From:In-Reply-To; b=fyxuZrWH2Gwgs+Q69WsAEbi9lok+EwZV5LFFTy39ebtdnnI2VqaZQA/qr1hV3/nqP aTSyWa1EoZotFEBH1yGm1ei7hA1pbSK5KAo92jYG/VEI/HRJ6O6PzLWbThAQvAOlwx ugOo1e9s9stRrXpTQOMuE2zwdU6Z/RlG+UeVf3Yg= Received: from DFLE103.ent.ti.com (dfle103.ent.ti.com [10.64.6.24]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 32NCQUjb118598 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 23 Mar 2023 07:26:30 -0500 Received: from DFLE112.ent.ti.com (10.64.6.33) by DFLE103.ent.ti.com (10.64.6.24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.16; Thu, 23 Mar 2023 07:26:29 -0500 Received: from fllv0039.itg.ti.com (10.64.41.19) by DFLE112.ent.ti.com (10.64.6.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.16 via Frontend Transport; Thu, 23 Mar 2023 07:26:29 -0500 Received: from [172.24.145.176] (ileaxei01-snat2.itg.ti.com [10.180.69.6]) by fllv0039.itg.ti.com (8.15.2/8.15.2) with ESMTP id 32NCQMRW009091; Thu, 23 Mar 2023 07:26:23 -0500 Message-ID: <5cae1874-9c10-a909-906c-160ce3f91286@ti.com> Date: Thu, 23 Mar 2023 17:56:21 +0530 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH 1/2] dt-bindings: drm/bridge: Add no-hpd property Content-Language: en-US To: Krzysztof Kozlowski , , , CC: , , , , , , , , , , , , , , , , , , , , , References: <20230316140823.234263-1-j-choudhary@ti.com> <20230316140823.234263-2-j-choudhary@ti.com> <79ce5fe8-9fb0-5caa-67a0-87dee7867856@ti.com> <55cfacf6-03e0-b9bc-83f3-3e9f2d7b2d4d@linaro.org> From: Jayesh Choudhary In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/03/23 20:47, Krzysztof Kozlowski wrote: > On 21/03/2023 15:28, Jayesh Choudhary wrote: >> >> >> On 21/03/23 18:08, Krzysztof Kozlowski wrote: >>> On 21/03/2023 13:02, Jayesh Choudhary wrote: >>>>> >>>>>> + type: boolean >>>>>> + description: >>>>>> + Set if the HPD line on the bridge isn't hooked up to anything or is >>>>>> + otherwise unusable. >>>>> >>>>> It's the property of the panel, not bridge. Unless you want to say that >>>>> bridge physically does not have HPD? Does it follow the standard in such >>>>> case? >>>> >>>> MHDP does have hpd. But the mhdp driver should handle the cases when the >>> >>> This is about bindings, not driver. Your driver can still handle this as >>> it wishes. >>> >>>> hpd pin of bridge is not connected to that of the DP-connector. This is >>>> to add support for that. (optional property) >>> >>> Which is indicated by panel no-hpd, right? >> >> Actually no panel is involved in this. For TI SoC J721S2, the data >> pipeline involves the bridge whose endpoint is directly the DP connector >> with compatible 'dp-connector'. And in the binding dp-connector.yaml, >> there isn't any 'no-hpd' property for this indication. >> >> Does this clarifies the issue? Or did I misinterpret your comment? > > Yes, then you only need to narrow which hardware does not have HPD > hooked up. Or at least clarify that it is not about driver having or not > having HPD control... > Okay. I will edit the commit message in v2. (after further review of the driver changes for this series) I will mention that the mhdp bridge can work without its HPD pin hooked up to the connector, but the current bridge driver throws an error when hpd line is not connected to the connector. For such cases, using this optional property, we can bypass the hpd detection and instead use the auxiliary channels connected to the DP connector to confirm the connection. Thanks, -Jayesh