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 5B7A4C636CC for ; Wed, 8 Feb 2023 14:49:57 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A0C0E10E7A2; Wed, 8 Feb 2023 14:49:50 +0000 (UTC) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 797C710E799; Wed, 8 Feb 2023 14:49:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1675867787; x=1707403787; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=UQXWo6TjDdebzIpdk/+ZIVkUr+YHexlGBDjSbMSM9rM=; b=Nyj6Ah0jmxv66Vfj5/+rkCHkfbvQy74A70VFEIyozfMQI1wdaZDrOKiP 9JXwZPC7V+N/9h4Qj8131JmwzdxhijGWHsC9MncPKR0eO9XCwxRcEYua+ fReClb+F9HnQncEJ6YMhwR8KBO3ggSb+xGGajcvmxMltwiwdS287GVcml zuVnjUpVpzhWXdn96D/3SXo8iN00aJIruhlc06ae15rT5mhLtgJEJcq6o UV20XWDPF+CRE4rmkXhqkr2s1KRYQvHL/VwSGCIfqLVvwuWGWao76nhqu 2LkCqDimUr5BDVajVnRTFQLkISAGArWkD4OlLALgKFJrXCWy8JxDRiA6O w==; X-IronPort-AV: E=McAfee;i="6500,9779,10615"; a="394404949" X-IronPort-AV: E=Sophos;i="5.97,281,1669104000"; d="scan'208";a="394404949" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2023 06:49:35 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10615"; a="730882821" X-IronPort-AV: E=Sophos;i="5.97,281,1669104000"; d="scan'208";a="730882821" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.55]) by fmsmga008.fm.intel.com with SMTP; 08 Feb 2023 06:49:32 -0800 Received: by stinkbox (sSMTP sendmail emulation); Wed, 08 Feb 2023 16:49:31 +0200 Date: Wed, 8 Feb 2023 16:49:31 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Pekka Paalanen Subject: Re: [PATCH 3/3] drm/connector: Deprecate split for BT.2020 in drm_colorspace enum Message-ID: References: <20230203020744.30745-1-joshua@froggi.es> <20230203020744.30745-3-joshua@froggi.es> <20230208111842.4d7aacb2@eldfell> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230208111842.4d7aacb2@eldfell> X-Patchwork-Hint: comment X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sebastian Wick , amd-gfx@lists.freedesktop.org, Uma Shankar , dri-devel@lists.freedesktop.org, Joshua Ashton , Vitaly.Prosyak@amd.com Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On Wed, Feb 08, 2023 at 11:18:42AM +0200, Pekka Paalanen wrote: > On Fri, 3 Feb 2023 16:02:51 +0200 > Ville Syrjälä wrote: > > > On Fri, Feb 03, 2023 at 02:52:50PM +0100, Sebastian Wick wrote: > > > On Fri, Feb 3, 2023 at 2:35 PM Ville Syrjälä > > > wrote: > > > > > > > > On Fri, Feb 03, 2023 at 01:59:07PM +0100, Sebastian Wick wrote: > > > > > On Fri, Feb 3, 2023 at 11:40 AM Ville Syrjälä > > > > > wrote: > > > > > > > > > > > > On Fri, Feb 03, 2023 at 02:07:44AM +0000, Joshua Ashton wrote: > > > > > > > Userspace has no way of controlling or knowing the pixel encoding > > > > > > > currently, so there is no way for it to ever get the right values here. > > > > > > > > > > > > That applies to a lot of the other values as well (they are > > > > > > explicitly RGB or YCC). The idea was that this property sets the > > > > > > infoframe/MSA/SDP value exactly, and other properties should be > > > > > > added to for use userspace to control the pixel encoding/colorspace > > > > > > conversion(if desired, or userspace just makes sure to > > > > > > directly feed in correct kind of data). > > > > > > > > > > I'm all for getting userspace control over pixel encoding but even > > > > > then the kernel always knows which pixel encoding is selected and > > > > > which InfoFrame has to be sent. Is there a reason why userspace would > > > > > want to control the variant explicitly to the wrong value? > > > > > > > > What do you mean wrong value? Userspace sets it based on what > > > > kind of data it has generated (or asked the display hardware > > > > to generate if/when we get explicit control over that part). > > > > > > Wrong in the sense of sending the YCC variant when the pixel encoding > > > is RGB for example. > > > > > > Maybe I'm missing something here but my assumption is that the kernel > > > always has to know the pixel encoding anyway. The color pipeline also > > > assumes that the pixel values are RGB. User space might be able to > > > generate YCC content but for subsampling etc the pixel encoding still > > > has to be explicitly set. > > > > The kernel doesn't really know much atm. In theory you can just > > configure the thing to do a straight passthough and put anything you > > want into your pixels. > > But it's impossible to use a YCbCr framebuffer and have that *not* > converted to RGB for the KMS color pipeline even if userspace wanted it > to be strictly pass-through, only to be converted again to YCbCr for > the cable, is it not? > > Even more so with 4:2:0. > > How could it be possible to stop the driver from doing those two > YUV-to-RGB and RGB-to-YCbCr conversions at the beginning and at the end > of the KMS color pipeline? You can stop the conversion at the start of the pipeline by using a "RGB" framebuffer. At the end of the pipe it's not possible with the current props. -- Ville Syrjälä Intel