From nobody Mon Feb 9 17:57:41 2026 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 3021B265623 for ; Wed, 28 Jan 2026 17:26:04 +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=1769621165; cv=none; b=dF4ofvs/tbYfHd/ycPYtSD85r5NTvFtrvZ0pzTBS/ZHO2FLlT6C2IjTQz3hroOosDsK4ELGE1xNsfn1rObwJ0EH0kDnGZVXADb6Vl00cXl604+mY6YIQjje22paBoMANz2+XWKgRaGBj6L+EcVpHg5mYfHk58EjQW8Ai/MKrku4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769621165; c=relaxed/simple; bh=0+4PliZFZn2ZEL7NwkuBYPphIbKpznlW8ky3nnE+a14=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=pdsHlaOHBhAvo7wedvVZ5om1vXjQbRBhGG/FAsIXEG3pmlaLaZB06oJ6u4QLOJWGiGYh032ooQHMmwz/oT2LfYbYU63aCJY3+OwzJgOmUo9PqnM78InL/zVplLRX3YxfiC/oUZL4nMnV2OUkVGVaSzDkzaa/qPQLstcKMdTtguE= 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=l/RCeaDC; 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="l/RCeaDC" Received: from [127.0.1.1] (91-158-153-178.elisa-laajakaista.fi [91.158.153.178]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 71BE518CB; Wed, 28 Jan 2026 18:25:23 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1769621124; bh=0+4PliZFZn2ZEL7NwkuBYPphIbKpznlW8ky3nnE+a14=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=l/RCeaDCETgXlyJvTBp6P54B2jqhi/sPvgWMbKhDWJ7QNTDJa5IbfBmHyba4CwGsj SCrfOMcMsBAk4VqdCWpdh4iEVkJ4cq0iaPzK6XQ11niEK3wp6fn0F3nis4Jq/P5+j/ jQCCYZo3wg2Zg/Kdd59BK26zi5Au7LDWD1UcuAts= From: Tomi Valkeinen Date: Wed, 28 Jan 2026 19:25:26 +0200 Subject: [PATCH v8 01/11] drm/fourcc: Add warning for bad bpp 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-Transfer-Encoding: quoted-printable Message-Id: <20260128-xilinx-formats-v8-1-9ea8adb70269@ideasonboard.com> References: <20260128-xilinx-formats-v8-0-9ea8adb70269@ideasonboard.com> In-Reply-To: <20260128-xilinx-formats-v8-0-9ea8adb70269@ideasonboard.com> To: Vishal Sagar , Anatoliy Klymenko , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Laurent Pinchart , Michal Simek Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Geert Uytterhoeven , Dmitry Baryshkov , Pekka Paalanen , Tomi Valkeinen X-Mailer: b4 0.15-dev-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=1814; i=tomi.valkeinen@ideasonboard.com; h=from:subject:message-id; bh=0+4PliZFZn2ZEL7NwkuBYPphIbKpznlW8ky3nnE+a14=; b=owEBbQKS/ZANAwAIAfo9qoy8lh71AcsmYgBpekail7GEf7ieuqRv7uv/kDEZDvLK0RPAIbNz4 fljyBlDrbGJAjMEAAEIAB0WIQTEOAw+ll79gQef86f6PaqMvJYe9QUCaXpGogAKCRD6PaqMvJYe 9VVQEACK6YFdQ9mnuV4a123HQG6WR3MxNCgB64Sp+5lubNNkrnPG9nuYR6k8H14+BL346x4IWPP 0wW+FIROeLXY06xL++3w4bHku/b9/J0I/24FBqVtdHVKlWs7ctHJk56YPMi8WYpQ66Vr7I2+uT0 h/SaGBgbu7ReHsKLUTuwibe/ckuDev0P+ENXxrmtowiAeIbyUdKQdl/XbNHFuEev06X5dGmkppp 3va2vtW/HBRbTMJAWQaTwwAmu6k1FZ/WKtj5N81qRwKXsF1vUy37m8rwBgmyJQOYAfLOUYXPxXK 2nzbo1pPgOOKiIccCDl5H2qLoAmM6/OTcia1nJ8wFQarPCYxCPIxzBW8kg3N4pfcFW5nRE80hDg ZoRfMbS8u4VDJD/9i8fytnaeu2VYGwaJefBHrrXkC509EAh5HXyIN16y7Gru0Z5lzsESuKU2CiY ceCHgNs+vVrQmEcXgv5XpNIXfcvkf7B6PiLEwLpwEAN8SZaO5y/jwwUDrPpZfw9PnTKPDaoEFQG RlBMz8EJ9XlnOp7JJqXDsVsKAW8Vy3yDVpT4fXbPoKoD6QeId9tyxTnWhfQRYWyLNeiBz0Wc+FM 31vZhnlCDyM3VLlKWFFOhwKiFLSr3r2JdqIsDUFNTs2xmNfltx07EoSawe3cAs/smJl3d60cnVz cUgNe3nw/v4vkdw== X-Developer-Key: i=tomi.valkeinen@ideasonboard.com; a=openpgp; fpr=C4380C3E965EFD81079FF3A7FA3DAA8CBC961EF5 drm_format_info_bpp() cannot be used for formats which do not have an integer bits-per-pixel in a pixel block. E.g. DRM_FORMAT_XV15's (not yet in upstream) plane 0 has three 10-bit pixels (Y components), and two padding bits, in a 4 byte block. That is 10.666... bits per pixel when considering the whole 4 byte block, which is what drm_format_info_bpp() does. Thus a driver that supports such formats cannot use drm_format_info_bpp(), It is a driver bug if this happens, but so handle wrong calls by printing a warning and returning 0. Reviewed-by: Laurent Pinchart Reviewed-by: Dmitry Baryshkov Signed-off-by: Tomi Valkeinen --- drivers/gpu/drm/drm_fourcc.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c index e0d533611040..e662aea9d105 100644 --- a/drivers/gpu/drm/drm_fourcc.c +++ b/drivers/gpu/drm/drm_fourcc.c @@ -491,12 +491,20 @@ EXPORT_SYMBOL(drm_format_info_block_height); */ unsigned int drm_format_info_bpp(const struct drm_format_info *info, int p= lane) { + unsigned int block_size; + if (!info || plane < 0 || plane >=3D info->num_planes) return 0; =20 - return info->char_per_block[plane] * 8 / - (drm_format_info_block_width(info, plane) * - drm_format_info_block_height(info, plane)); + block_size =3D drm_format_info_block_width(info, plane) * + drm_format_info_block_height(info, plane); + + if (info->char_per_block[plane] * 8 % block_size) { + pr_warn("unable to return an integer bpp\n"); + return 0; + } + + return info->char_per_block[plane] * 8 / block_size; } EXPORT_SYMBOL(drm_format_info_bpp); =20 --=20 2.43.0