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 093E5C77B7E for ; Mon, 29 May 2023 11:12:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230212AbjE2LMf (ORCPT ); Mon, 29 May 2023 07:12:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229570AbjE2LMd (ORCPT ); Mon, 29 May 2023 07:12:33 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2503CCF for ; Mon, 29 May 2023 04:12:32 -0700 (PDT) Received: from [192.168.88.20] (91-154-35-171.elisa-laajakaista.fi [91.154.35.171]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id B211B836; Mon, 29 May 2023 13:12:06 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1685358729; bh=ADkBV2LVS+YgVqFYYD4O2XlRfoS6+tQg/VZ+VEf6b1Y=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=hohLMmFWvioA5RJ9d0FwjFsyEu/C+X32za6b6Q8VbtETTJPfBcpsbBO2UTP6fWEpX 0Tu4bHMD5+YLxhDhQdTyuFl8hBfvh1VzjQxLBAlp4pPUNhp1FPdtJridqyTs+sp0G1 NarhUBv1yVAKKVnq4jzH1bgbKVVHsyCiXAz0itis= Message-ID: <5d207be0-c8f0-7c68-91b2-d5ef873ca6cc@ideasonboard.com> Date: Mon, 29 May 2023 14:12:23 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH v6 3/8] drm/bridge: mhdp8546: Add minimal format negotiation Content-Language: en-US To: Aradhya Bhatia , neil.armstrong@linaro.org, Jyri Sarha , David Airlie , Daniel Vetter , Laurent Pinchart , Andrzej Hajda , Robert Foss , Jonas Karlman , Jernej Skrabec , Rahul T R , Swapnil Jakhade , Boris Brezillon , Francesco Dolcini Cc: DRI Development List , Linux Kernel List , Nishanth Menon , Vignesh Raghavendra , Devarsh Thakkar , Jayesh Choudhary References: <20230509093036.3303-1-a-bhatia1@ti.com> <20230509093036.3303-4-a-bhatia1@ti.com> <305382fd-2312-59d9-e2d3-25a17e0a2158@linaro.org> <363d3089-48d4-5663-68e8-ecf0eb4e3e0e@ti.com> <9f98fb99-eaf4-657c-fd2e-b2e81d9cb109@ideasonboard.com> From: Tomi Valkeinen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/05/2023 08:37, Aradhya Bhatia wrote: >> Btw, we seem to be missing get-output-fmt from the mdhp driver. > Yes, we are. > > With the drm_bridge_attach call added, the display-connector bridge will > assign MEDIA_BUS_FMT_FIXED as the default output format. And most > bridges support only their primary output bus format in their > get-output-fmt hooks. I suppose it would be RGB121212_1X36 in mhdp8546's > case. > > Do we require this when there is no comprehensive way to determine if > another bus format may be more suitable (depending on the hardware > configurations)? If I recall right, mhdp supports other formats than RGB121212_1X36 on the input side (different bit depths and also yuv). On the output side, even if the input is 12 bits per component, when connected to a normal monitor, the output bpc would be 8. I'm not sure if any of that matters, as nobody (?) will use the output format of mhdp, as it just goes "outside" to the monitor, and it is the mhdp driver that negotiates a suitable output format with the monitor. Tomi