From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (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 C98E3366823 for ; Mon, 8 Jun 2026 11:19:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780917585; cv=pass; b=IidWX0e83MLuywf7S7wQGJurBYvs+VRFVUX2I7St5Yzxb94vqQLQWcNnuvYC0Iu6CfXw1pc5MaKQw1VCqX0OGL5O6OkGad07MNEtl3OkZ7/hZskpjNE07xCtbYAVpzAu5rz6b90Kt/RvVBVzd1WwoJxcK/QuXW20jrlKiCsUs7A= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780917585; c=relaxed/simple; bh=digO9QWRFlodClRJWqrqmT12MrUla6qzg5/xGtnlYuk=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=kZqpzxzypp7/gOgumimHpuT1FV/+2w3MIQy5xE/ahVZHiNSHWYsKARDe4BbVcTLiGD6wQ8MHRzi3Kq09Cyi+S8kdb9JiowEyUbFshus+grJRWbpQo1GQOBDTV59LQDKerDwoqluIaM4FNMfW1IHB7O7CZgogmeofZC3dKn4ocLU= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b=RDPAYOoA; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=nicolas.frattaroli@collabora.com header.b="RDPAYOoA" ARC-Seal: i=1; a=rsa-sha256; t=1780917568; cv=none; d=zohomail.com; s=zohoarc; b=KWD5usv1C0fTY2qWIgRJmVePHy2/J3m0gJmUb6F1/48oOBeASRIYYkRq6Ai18xWykr7fkysS5cwBnCFH4I4vO6EdJkn6de5zsq/6fG5SPs99rcdOmTHmcHdxsaWXbtuzU8DZDkZxFEh76dp7ikVINGTxhRRU96lwZJiyRyqQ3vA= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1780917568; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=Fiq0mlSYnjDuCrPe/1XJ673qK5vnmNKxf/K7jiJ5Bak=; b=Z5Y5DO4TWEsdoOBxYfxXt6Ev3SB2oFzJc2Z1iw2H48A9PxDFG3rr99RBGjFIROH1anV8dtng/8D8IeyCbh/wCop7CYhrnr1dMVYB0f+S2U/yEAx/As798dk+gyBxR1liTvBwon5LwYfeG/hvfjgqZ2y8lQYXp7aWRgDJ7yBrMWc= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=nicolas.frattaroli@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1780917568; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=Fiq0mlSYnjDuCrPe/1XJ673qK5vnmNKxf/K7jiJ5Bak=; b=RDPAYOoAhvJNIcJVlY59FUIJT8KM8YpSpUvMZl4gserwGaCgID4a7LG7LoO5+MA+ IPnV518yADrpGvYuXdWGWzskI7+S7YbDP6A2bpD/UQ5Fw6ZozFB3eAP5ssP3RZm/ncS r66wayPMF+e4rAV8FOBTKJcCjCc7og50gWsnf1kM= Received: by mx.zohomail.com with SMTPS id 1780917565653660.7662547061447; Mon, 8 Jun 2026 04:19:25 -0700 (PDT) From: Nicolas Frattaroli Date: Mon, 08 Jun 2026 13:19:07 +0200 Subject: [PATCH 1/2] drm/display: hdmi: Only allow BPC values of 8, 10, 12 and 16 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: 7bit Message-Id: <20260608-hdmi-max-bpc-fix-v1-1-6e8dcebc7274@collabora.com> References: <20260608-hdmi-max-bpc-fix-v1-0-6e8dcebc7274@collabora.com> In-Reply-To: <20260608-hdmi-max-bpc-fix-v1-0-6e8dcebc7274@collabora.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Dmitry Baryshkov Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, Nicolas Frattaroli X-Mailer: b4 0.15.2 As per the comment in sink_supports_format_bpc(), CTA-861-F defines that only bits-per-channel values of 8, 10, 12 and 16 are allowed for HDMI. Allowing more than this has surprising consequences for the atomic check phase. The HDMI state helpers may accidentally conclude that a sink supports 11bpc if a caller asks for it. Fix this by exiting early if the bpc value doesn't match one of those given in the standard. Fixes: 26ff1c38fc29 ("drm/connector: hdmi: Compute bpc and format automatically") Signed-off-by: Nicolas Frattaroli --- drivers/gpu/drm/display/drm_hdmi_state_helper.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/gpu/drm/display/drm_hdmi_state_helper.c b/drivers/gpu/drm/display/drm_hdmi_state_helper.c index a331ebdd65af..8303475ec021 100644 --- a/drivers/gpu/drm/display/drm_hdmi_state_helper.c +++ b/drivers/gpu/drm/display/drm_hdmi_state_helper.c @@ -420,6 +420,16 @@ sink_supports_format_bpc(const struct drm_connector *connector, return false; } + switch (bpc) { + case 8: + case 10: + case 12: + case 16: + break; + default: + return false; + } + if (!info->is_hdmi && (format != DRM_OUTPUT_COLOR_FORMAT_RGB444 || bpc != 8)) { drm_dbg_kms(dev, "DVI Monitors require an RGB output at 8 bpc\n"); -- 2.54.0