From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C9AB82FE58D for ; Wed, 28 Jan 2026 18:10:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769623841; cv=none; b=epzQ7yzC9n6tQSHhM2MLSmWCscyoXNvg7wYa6ch1Y+baQTMajUwaEJ1oJkLPYm5I0t9Wv4N3BRPkIJy4hZ8svtWkJG1eyNoOxjbxWXiInLIWbjUrSv1CSm3Ek9jIXZMQVCtOmwFJp3iAh9LNHE0H7UfO24kUPSKpnv5fK7oyyV0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769623841; c=relaxed/simple; bh=DJDOdIFvJ35ng6Ss7jpNp+I4hfOTBmI0yhLVXDrDUf0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HkjHBfEU7TivDYRKsZ2Av9rD7uzPA/8neTQCwOrcM1YpPFEB7DDqH3vah0Cfrzd1+Ne6K+fn85+u4PuDwy3mVau1qXUG4md1FN79SJgHRNjB889wJ5R9agG4S6h6QrxXDfBs9vK5R6FlZvyXLkzb2nbWe8urHokiTaGkbxrcezM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=tmLPDZoi; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="tmLPDZoi" Received: from killaraus.ideasonboard.com (2001-14ba-703d-e500--2a1.rev.dnainternet.fi [IPv6:2001:14ba:703d:e500::2a1]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 64752581; Wed, 28 Jan 2026 19:10:00 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1769623800; bh=DJDOdIFvJ35ng6Ss7jpNp+I4hfOTBmI0yhLVXDrDUf0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tmLPDZoivpwL2F0XqQHJRCtr8n4D1+fGg86jSBoMivWlq19+STaTEKZdQGJbYhc2F gDYdHbPUgZ2wj/C9YZeKYZba44cbDMt07v88KUd6yzUG22f+VnK9AOEa1L+Sdg/en4 CRBcGy0btV1ewfO5neFeai+bprFxdIHpIAt7oNik= Date: Wed, 28 Jan 2026 20:10:35 +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 v8 03/11] drm/fourcc: Add DRM_FORMAT_Y8 Message-ID: <20260128181035.GD3225981@killaraus> References: <20260128-xilinx-formats-v8-0-9ea8adb70269@ideasonboard.com> <20260128-xilinx-formats-v8-3-9ea8adb70269@ideasonboard.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260128-xilinx-formats-v8-3-9ea8adb70269@ideasonboard.com> On Wed, Jan 28, 2026 at 07:25:28PM +0200, Tomi Valkeinen wrote: > Add greyscale Y8 format. > > The 8-bit greyscale format has been discussed before, and the earlier > guidance was to use DRM_FORMAT_R8, as a single-channel 8-bit pixel. > > However, adding DRM_FORMAT_Y8 makes sense, we can mark it as 'is_yuv' in > the drm_format_info, and this can help the drivers handle e.g. > full/limited range. This will distinguish two single-channel formats: > R8, which is a RGB format with the same value for all components, and > Y8, which is a Y-only YCbCr format, with Cb and Cr being neutral. > > Acked-by: Dmitry Baryshkov > Reviewed-by: Pekka Paalanen > Reviewed-by: Vishal Sagar > Signed-off-by: Tomi Valkeinen Reviewed-by: Laurent Pinchart > --- > drivers/gpu/drm/drm_fourcc.c | 1 + > include/uapi/drm/drm_fourcc.h | 9 +++++++++ > 2 files changed, 10 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..e4451668499a 100644 > --- a/include/uapi/drm/drm_fourcc.h > +++ b/include/uapi/drm/drm_fourcc.h > @@ -459,6 +459,15 @@ 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. > + */ > + > +#define DRM_FORMAT_Y8 fourcc_code('G', 'R', 'E', 'Y') /* 8-bit Y-only */ > > /* > * Format Modifiers: -- Regards, Laurent Pinchart