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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 239DEC2BD09 for ; Fri, 28 Jun 2024 16:41:02 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 96A1510E03E; Fri, 28 Jun 2024 16:41:01 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=jookia.org header.i=@jookia.org header.b="QsZGUPCn"; dkim-atps=neutral Received: from out-175.mta1.migadu.com (out-175.mta1.migadu.com [95.215.58.175]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5220010E03E for ; Fri, 28 Jun 2024 16:40:59 +0000 (UTC) X-Envelope-To: jani.nikula@linux.intel.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jookia.org; s=key1; t=1719592856; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=U88aOQSqT01+NP3zcbq60KCUzmQTSGOugyTyS/riJNQ=; b=QsZGUPCnEh3DuJ3GkQXXuAcR3AniphwAx4OzyRv3l4XguZx/3+QRDksAKnwUViZOSNZRR8 owcillfhfKTN1sg5pZpzJcObvp+vwORSJKA0RJpwysoD0nZaBPNAdt4Tdpd3Pf8k6FAxy+ trXBUefxICGDy621NzJPEcCPnnrAxpWleBznS1c7rblsrDPp23n28mdF3sFR6C5qbk43W1 n8ZAvta2xUX0WTskx+vuFcV07A7c7wJVaFMY02Gv/qs8+VJ3hV+VdtpZo8qQQTs2FkAIg5 s4yoHQ5fQtwQEqNkQrB68Uvcf0JYJf15rZRbLDsMoUoZ0jpifWvN5faZ1IvwiQ== X-Envelope-To: dri-devel@lists.freedesktop.org Date: Sat, 29 Jun 2024 02:39:16 +1000 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: John Watts To: Jani Nikula Cc: dri-devel@lists.freedesktop.org Subject: Re: How to specify panel bit order in driver? Message-ID: References: <87le2pbjdf.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87le2pbjdf.fsf@intel.com> X-Migadu-Flow: FLOW_OUT X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Hi Jani, On Fri, Jun 28, 2024 at 10:45:48AM +0300, Jani Nikula wrote: > Might be helpful to actually point at the source code or commits or > something. The source code is here: drivers/gpu/drm/panel/panel-newvision-nv3052c.c It's just a standard MIPI DBI panel. It reports using an RGB888 bus format. > Maybe look at include/uapi/drm/drm_fourcc.h, and how the DRM_FORMAT_* > macros are used. > > Can't help you with device tree, but maybe this gives you pointers to > other places for examples. Currently it works like this: - DRM uses 24-bit depth - CRTC puts out a 24-bit signal - This gets output over LCD pins - The PCB drops 2 bits per channel by wiring 6 pins to GND - The panel is told to only use 18 bits Getting DRM to use MEDIA_BUS_FMT_RGB666_1X18 would be nice and allow the panel to auto-detect which bits to use. But the bus format is set in the panel :( Where is the bus format usually set for cases where a board only supports a physical format? > HTH, > Jani. > > > -- > Jani Nikula, Intel John.