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 40CE6D25B48 for ; Wed, 28 Jan 2026 11:49:59 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2Wfwd4ogTgl4DnsM13zVZopRhXqibquoW/vrOHj/oIE=; b=Q5hVvXfhQzW3ZAZp7UArXpQe00 K9w1Vv5Ys6n44PSdzWNCA36R6TP9UHe5R+xjy53O3K4ZJQaJkNNpD5YiUJWNIn4hxIVb8WW+CVLU2 WZTtk5+M8vyXEevdK59woOtEyppv3B4JoQmWnUvCV3rJilDQGXKHRcr+OD8aqYj8Gp9jHvP+GAa2S gxLhGl7p2mAwDETr1tJDCo4IdS2Za8pMSrDLXOEc0rKwuYFGS1ME9oiqeRnzroGP2zs1u35fleksL JQbGdCqYSHehgfdvd6Ow/54hg3EBUwc6Yo9TIn7LMIxyly0RfYWgl6wO9hGmj1YqO2sRV9Mu2YSPF WRr2VB9g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vl43T-0000000FxLE-3hGw; Wed, 28 Jan 2026 11:49:51 +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 1vl43Q-0000000FxKr-1nZ9 for linux-arm-kernel@lists.infradead.org; Wed, 28 Jan 2026 11:49:50 +0000 Received: from pendragon.ideasonboard.com (2001-14ba-703d-e500--2a1.rev.dnainternet.fi [IPv6:2001:14ba:703d:e500::2a1]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id AE752C6F; Wed, 28 Jan 2026 12:49:05 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1769600945; bh=J5GRkADBM7kHKN0psYa8w2c8cQmmZlbTkq09npe3U8Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ji62OmoqFXpggqhKXPObU9raamBfIqFvqb8PaDcnivhIVJZqWBp7w5PVnbnYlkc3W 4NznQ3zv+AEP4DgFUva9+LXeYK8sZz1PahE875MELTQRFXhf0Mg5fIB0iOFxlay+sb o6uNTEyS8Uv20bY4Gb1wJKovSTTRAKfP7w+9T++E= Date: Wed, 28 Jan 2026 13:49:41 +0200 From: Laurent Pinchart To: Tomi Valkeinen 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 Subject: Re: [PATCH v7 03/11] drm/fourcc: Add DRM_FORMAT_Y8 Message-ID: <20260128114941.GF2558360@killaraus> References: <20251201-xilinx-formats-v7-0-1e1558adfefc@ideasonboard.com> <20251201-xilinx-formats-v7-3-1e1558adfefc@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20251201-xilinx-formats-v7-3-1e1558adfefc@ideasonboard.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260128_034948_946747_19D2D6E4 X-CRM114-Status: GOOD ( 18.38 ) 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 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. > + */ > + > +#define DRM_FORMAT_Y8 fourcc_code('G', 'R', 'E', 'Y') /* 8-bit Y-only */ I would have gone for 'Y', '8', ' ', ' ' > > /* > * Format Modifiers: -- Regards, Laurent Pinchart