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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 4C6FCD3F07A for ; Wed, 28 Jan 2026 15:38:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1FmQ9T5bTzUOeTMZ/GidnPimVca9kBPQJHSbWWZMOvE=; b=E16VkpQamsTMDhxyeMmvfUWGQE eiSNLz8gbh+mNAKWaQEJHiG+yf50ghmfzBSfHlHEHF4Jguf3CvDlOEj9Nt2rWGOpIJkt7x3ikRezB 91pw4MXnN678avL0U89gB8YvkBK7lUkJPiq/6dobKCZZI0bpS5o/gijj3k7vQi5J/lIG9cz2faDc3 h/66kjVkGtqjj9YlcY0VWha2oXKDszpdg3n+KzD3kwnEXfVkPASIMrLvLZu/vFnNaSOD7wHDsw5rv 2kTnkOZd+jbRwH5itt1Nv1yLzdQR8s24ibvs3092rTBaxAC6SDoCy1RAOK8TU4hSJ+YbchXmnHibT YONu4BhQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vl7cb-0000000GIl6-0woA; Wed, 28 Jan 2026 15:38:21 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vl7cY-0000000GIjc-1DAM for linux-arm-kernel@lists.infradead.org; Wed, 28 Jan 2026 15:38:19 +0000 Received: from [192.168.88.20] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id A8176581; Wed, 28 Jan 2026 16:37:37 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1769614658; bh=A6uNF3pGbxHXRgksiH1d6qGq/WlSIjKiTxUk3hZZqXQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=pl/Mpwn3PX2QZTZfwl+foSltm6Rl8saFpbtkTA2sPon3qE7jZotj1VOZjXgqTUtTT VD/qAV0PDHAzxRJiY5rrvOVsINvCpwyFIpiDLauw0vBM7nGJeAti/iGukAmhr2JKc+ T4+yqXDfyg9i81V/74Hn0xkNs4Yib4zDFxgaoUXI= Message-ID: <116b508e-0853-4b0b-966e-47d84167d4be@ideasonboard.com> Date: Wed, 28 Jan 2026 17:38:11 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 03/11] drm/fourcc: Add DRM_FORMAT_Y8 To: Laurent Pinchart Cc: Vishal Sagar , Anatoliy Klymenko , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Michal Simek , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Geert Uytterhoeven , Dmitry Baryshkov , Pekka Paalanen , Pekka Paalanen , Dmitry Baryshkov References: <20251201-xilinx-formats-v7-0-1e1558adfefc@ideasonboard.com> <20251201-xilinx-formats-v7-3-1e1558adfefc@ideasonboard.com> <20260128114941.GF2558360@killaraus> From: Tomi Valkeinen Content-Language: en-US Autocrypt: addr=tomi.valkeinen@ideasonboard.com; keydata= xsFNBE6ms0cBEACyizowecZqXfMZtnBniOieTuFdErHAUyxVgtmr0f5ZfIi9Z4l+uUN4Zdw2 wCEZjx3o0Z34diXBaMRJ3rAk9yB90UJAnLtb8A97Oq64DskLF81GCYB2P1i0qrG7UjpASgCA Ru0lVvxsWyIwSfoYoLrazbT1wkWRs8YBkkXQFfL7Mn3ZMoGPcpfwYH9O7bV1NslbmyJzRCMO eYV258gjCcwYlrkyIratlHCek4GrwV8Z9NQcjD5iLzrONjfafrWPwj6yn2RlL0mQEwt1lOvn LnI7QRtB3zxA3yB+FLsT1hx0va6xCHpX3QO2gBsyHCyVafFMrg3c/7IIWkDLngJxFgz6DLiA G4ld1QK/jsYqfP2GIMH1mFdjY+iagG4DqOsjip479HCWAptpNxSOCL6z3qxCU8MCz8iNOtZk DYXQWVscM5qgYSn+fmMM2qN+eoWlnCGVURZZLDjg387S2E1jT/dNTOsM/IqQj+ZROUZuRcF7 0RTtuU5q1HnbRNwy+23xeoSGuwmLQ2UsUk7Q5CnrjYfiPo3wHze8avK95JBoSd+WIRmV3uoO rXCoYOIRlDhg9XJTrbnQ3Ot5zOa0Y9c4IpyAlut6mDtxtKXr4+8OzjSVFww7tIwadTK3wDQv Bus4jxHjS6dz1g2ypT65qnHen6mUUH63lhzewqO9peAHJ0SLrQARAQABzTBUb21pIFZhbGtl aW5lbiA8dG9taS52YWxrZWluZW5AaWRlYXNvbmJvYXJkLmNvbT7CwY4EEwEIADgWIQTEOAw+ ll79gQef86f6PaqMvJYe9QUCX/HruAIbAwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgAAKCRD6 PaqMvJYe9WmFD/99NGoD5lBJhlFDHMZvO+Op8vCwnIRZdTsyrtGl72rVh9xRfcSgYPZUvBuT VDxE53mY9HaZyu1eGMccYRBaTLJSfCXl/g317CrMNdY0k40b9YeIX10feiRYEWoDIPQ3tMmA 0nHDygzcnuPiPT68JYZ6tUOvAt7r6OX/litM+m2/E9mtp8xCoWOo/kYO4mOAIoMNvLB8vufi uBB4e/AvAjtny4ScuNV5c5q8MkfNIiOyag9QCiQ/JfoAqzXRjVb4VZG72AKaElwipiKCWEcU R4+Bu5Qbaxj7Cd36M/bI54OrbWWETJkVVSV1i0tghCd6HHyquTdFl7wYcz6cL1hn/6byVnD+ sR3BLvSBHYp8WSwv0TCuf6tLiNgHAO1hWiQ1pOoXyMEsxZlgPXT+wb4dbNVunckwqFjGxRbl Rz7apFT/ZRwbazEzEzNyrBOfB55xdipG/2+SmFn0oMFqFOBEszXLQVslh64lI0CMJm2OYYe3 PxHqYaztyeXsx13Bfnq9+bUynAQ4uW1P5DJ3OIRZWKmbQd/Me3Fq6TU57LsvwRgE0Le9PFQs dcP2071rMTpqTUteEgODJS4VDf4lXJfY91u32BJkiqM7/62Cqatcz5UWWHq5xeF03MIUTqdE qHWk3RJEoWHWQRzQfcx6Fn2fDAUKhAddvoopfcjAHfpAWJ+ENc7BTQROprNHARAAx0aat8GU hsusCLc4MIxOQwidecCTRc9Dz/7U2goUwhw2O5j9TPqLtp57VITmHILnvZf6q3QAho2QMQyE DDvHubrdtEoqaaSKxKkFie1uhWNNvXPhwkKLYieyL9m2JdU+b88HaDnpzdyTTR4uH7wk0bBa KbTSgIFDDe5lXInypewPO30TmYNkFSexnnM3n1PBCqiJXsJahE4ZQ+WnV5FbPUj8T2zXS2xk 0LZ0+DwKmZ0ZDovvdEWRWrz3UzJ8DLHb7blPpGhmqj3ANXQXC7mb9qJ6J/VSl61GbxIO2Dwb xPNkHk8fwnxlUBCOyBti/uD2uSTgKHNdabhVm2dgFNVuS1y3bBHbI/qjC3J7rWE0WiaHWEqy UVPk8rsph4rqITsj2RiY70vEW0SKePrChvET7D8P1UPqmveBNNtSS7In+DdZ5kUqLV7rJnM9 /4cwy+uZUt8cuCZlcA5u8IsBCNJudxEqBG10GHg1B6h1RZIz9Q9XfiBdaqa5+CjyFs8ua01c 9HmyfkuhXG2OLjfQuK+Ygd56mV3lq0aFdwbaX16DG22c6flkkBSjyWXYepFtHz9KsBS0DaZb 4IkLmZwEXpZcIOQjQ71fqlpiXkXSIaQ6YMEs8WjBbpP81h7QxWIfWtp+VnwNGc6nq5IQDESH mvQcsFS7d3eGVI6eyjCFdcAO8eMAEQEAAcLBXwQYAQIACQUCTqazRwIbDAAKCRD6PaqMvJYe 9fA7EACS6exUedsBKmt4pT7nqXBcRsqm6YzT6DeCM8PWMTeaVGHiR4TnNFiT3otD5UpYQI7S suYxoTdHrrrBzdlKe5rUWpzoZkVK6p0s9OIvGzLT0lrb0HC9iNDWT3JgpYDnk4Z2mFi6tTbq xKMtpVFRA6FjviGDRsfkfoURZI51nf2RSAk/A8BEDDZ7lgJHskYoklSpwyrXhkp9FHGMaYII m9EKuUTX9JPDG2FTthCBrdsgWYPdJQvM+zscq09vFMQ9Fykbx5N8z/oFEUy3ACyPqW2oyfvU CH5WDpWBG0s5BALp1gBJPytIAd/pY/5ZdNoi0Cx3+Z7jaBFEyYJdWy1hGddpkgnMjyOfLI7B CFrdecTZbR5upjNSDvQ7RG85SnpYJTIin+SAUazAeA2nS6gTZzumgtdw8XmVXZwdBfF+ICof 92UkbYcYNbzWO/GHgsNT1WnM4sa9lwCSWH8Fw1o/3bX1VVPEsnESOfxkNdu+gAF5S6+I6n3a ueeIlwJl5CpT5l8RpoZXEOVtXYn8zzOJ7oGZYINRV9Pf8qKGLf3Dft7zKBP832I3PQjeok7F yjt+9S+KgSFSHP3Pa4E7lsSdWhSlHYNdG/czhoUkSCN09C0rEK93wxACx3vtxPLjXu6RptBw 3dRq7n+mQChEB1am0BueV1JZaBboIL0AGlSJkm23kw== In-Reply-To: <20260128114941.GF2558360@killaraus> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260128_073818_470539_F13EC01D X-CRM114-Status: GOOD ( 20.07 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 28/01/2026 13:49, Laurent Pinchart wrote: > Hi Tomi, > > Thank you for the patch. > > On Mon, Dec 01, 2025 at 02:18:45PM +0200, Tomi Valkeinen wrote: >> Add greyscale Y8 format. > > I would explain here why we need a new format and can't just use > DRM_FORMAT_R8. You don't need to convince me, but I think it's important > to summarize the rationale should someone later wonder why we introduced > this. > >> Acked-by: Dmitry Baryshkov >> Reviewed-by: Pekka Paalanen >> Reviewed-by: Vishal Sagar >> Signed-off-by: Tomi Valkeinen >> --- >> drivers/gpu/drm/drm_fourcc.c | 1 + >> include/uapi/drm/drm_fourcc.h | 10 ++++++++++ >> 2 files changed, 11 insertions(+) >> >> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c >> index b22ef86428a1..a39b9d7a5b62 100644 >> --- a/drivers/gpu/drm/drm_fourcc.c >> +++ b/drivers/gpu/drm/drm_fourcc.c >> @@ -275,6 +275,7 @@ const struct drm_format_info *__drm_format_info(u32 format) >> { .format = DRM_FORMAT_YVU422, .depth = 0, .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 2, .vsub = 1, .is_yuv = true }, >> { .format = DRM_FORMAT_YUV444, .depth = 0, .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 1, .vsub = 1, .is_yuv = true }, >> { .format = DRM_FORMAT_YVU444, .depth = 0, .num_planes = 3, .cpp = { 1, 1, 1 }, .hsub = 1, .vsub = 1, .is_yuv = true }, >> + { .format = DRM_FORMAT_Y8, .depth = 8, .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1, .is_yuv = true }, >> { .format = DRM_FORMAT_NV12, .depth = 0, .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 2, .is_yuv = true }, >> { .format = DRM_FORMAT_NV21, .depth = 0, .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 2, .is_yuv = true }, >> { .format = DRM_FORMAT_NV16, .depth = 0, .num_planes = 2, .cpp = { 1, 2, 0 }, .hsub = 2, .vsub = 1, .is_yuv = true }, >> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h >> index 6c786701238e..5cfc188c4e72 100644 >> --- a/include/uapi/drm/drm_fourcc.h >> +++ b/include/uapi/drm/drm_fourcc.h >> @@ -459,6 +459,16 @@ extern "C" { >> #define DRM_FORMAT_YUV444 fourcc_code('Y', 'U', '2', '4') /* non-subsampled Cb (1) and Cr (2) planes */ >> #define DRM_FORMAT_YVU444 fourcc_code('Y', 'V', '2', '4') /* non-subsampled Cr (1) and Cb (2) planes */ >> >> +/* >> + * Y-only (greyscale) formats >> + * >> + * The Y-only formats are handled similarly to the YCbCr formats in the display >> + * pipeline, with the Cb and Cr implicitly neutral (0.0 in nominal values). This >> + * also means that COLOR_RANGE property applies to the Y-only formats. >> + * > > Extra blank line. I'll drop. >> + */ >> + >> +#define DRM_FORMAT_Y8 fourcc_code('G', 'R', 'E', 'Y') /* 8-bit Y-only */ > > I would have gone for 'Y', '8', ' ', ' ' Missed these comments earlier... Yes, "Y8 " makes sense. But I was trying to be nice, as there are already users for Y8 ("GREY") with BSP kernels, and changing the fourcc code would break their userspace... Tomi