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 34EC83D79FE for ; Thu, 18 Jun 2026 18:54:58 +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=1781808900; cv=pass; b=LNZlmuSeHHEDDBjzHs4SSY/P+uRR7FWCGHDOpOeyxEOS9fScdPKUM4ApV6h93iQGXsNowza/8V8m+O1mJB9/OtQGzpMPjKRw0hXrS7YPWwbvF27oNZPNPfwvNri/lThnMzeKaxQz9TgxpPM6YcldnG1631Uxvx2qz2id3SphoVc= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781808900; c=relaxed/simple; bh=AWoNNph5h/FfNwQl2S5jqJ8Z4RL3wSJoT2SqgHxeAyM=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=hywP3XUTeBZ1H4Aj3hrCZNKuNMmJ1HZpk/PUZqlIOZj2E0jBmc6zFUalqtX0I8aobkW3aeT7g39CE8uN/6ykxbV8SELRsO+xEDmBETeKRUObHZwjOZKXt/NRmVV4pVhB79utU7p9s67KQEWZ6k6qgEiV7lXe+j/0XDeSutT2VBY= 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=Pzd9ApkQ; 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="Pzd9ApkQ" ARC-Seal: i=1; a=rsa-sha256; t=1781808881; cv=none; d=zohomail.com; s=zohoarc; b=eLsJONgQB7mlV51qQo3iPV1In82KGGGdBNMVuWhYMRlnD+xd6eUdRbqYCtjrKNPp9EcO+MIaTijgo8LZrSNCxQlPQXfVVssE/gn84iYAFeq+HZyoKdzYQPH1G/g5p8JSsFx2TrgSjC/I0Mr7GHGH7LMOIsWqVEvHPKRN0/YIMK4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1781808881; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=6U2vsnDoMQqT2ncVs5Tg7NhOdUBLlXq+U06ka+M4MXc=; b=QPwQf7bdE07fu+QkX2s/x20ySzaNp2zJOGUNURlFjhAI7N3DXrkeMM73amirpOw2ilEWVnxjuy60q9sn6zv2WvU58/ATNtK5ajDZ0gqpJTIXon9n440Hp0QyfvClew6/1CGsdUMRFPB8KXTV9Y4pbeFJG0/JTxc1m1mWewmIz1I= 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=1781808881; s=zohomail; d=collabora.com; i=nicolas.frattaroli@collabora.com; h=From:From:Subject:Subject:Date:Date:Message-Id:Message-Id:MIME-Version:Content-Type:Content-Transfer-Encoding:To:To:Cc:Cc:Reply-To; bh=6U2vsnDoMQqT2ncVs5Tg7NhOdUBLlXq+U06ka+M4MXc=; b=Pzd9ApkQI0a0cmhO9Kbxj5TGwq+Vljm4juXf+VzHnK9DNwLq2h/uu3utXf7LoPrT enAka5KAJfgo8XkHsWOQSht/h5r7Xt0vk/V/fW5Rs4lAXOfHeLd2toExJ6ahS30Xu4U UIGDyCgC0cP4RLPay5fes6nE/1vEw8wDS31bogSw= Received: by mx.zohomail.com with SMTPS id 1781808879173202.04730720142072; Thu, 18 Jun 2026 11:54:39 -0700 (PDT) From: Nicolas Frattaroli Subject: [PATCH v2 0/2] Make HDMI state helpers handle odd max bpc requests Date: Thu, 18 Jun 2026 20:54:22 +0200 Message-Id: <20260618-hdmi-max-bpc-fix-v2-0-7b67f489b0cc@collabora.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-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAAAAAAAC/3WOwQ6CMBBEf4Xs2dUCBpCT/2E8tGWVNZZiWwmG8 O9W4OppM5uZNzOBJ8fkoU4mcDSwZ9tFke0S0K3s7oTcRA2ZyApRiArbxjAaOaLqNd54xFLkIj2 VRV7lR4ix3lF8L8jLddX+rR6kw4+zORy93rErrDZQ0hNqawyHOmmcwcD9Ybvwg7Tsg3WfZeaQL pn/i4YUBRZUNZqULrPyeNb2+ZTKOrmPJXCd5/kL6RH6XfkAAAA= X-Change-ID: 20260608-hdmi-max-bpc-fix-703019763834 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 With the "max bpc" KMS connector property, userspace can arbitrarily restrict the upper end of the bits-per-component range. This is fine and good, except the HDMI state helpers never considered that max_bpc could be influenced by a userspace setting, so assumed it'll always be an even value from the HDMI standards. This, unfortunately, is not the world we live in anymore. Patch 1 corrects sink_supports_format_bpc to return false on BPCs outside of what HDMI allows. Patch 2 then corrects handling of odd-numbered max bpcs by rounding the loop start value down to an even number instead. It also adds a KUnit test to make sure nobody breaks this again in the future. Signed-off-by: Nicolas Frattaroli --- Changes in v2: - Use rounddown() from linux/math.h instead of the bespoke rounding. No functional changes. - Note: switch statement in patch 1 kept as-is, as 14bpc is not allowed by HDMI it seems. - Link to v1: https://patch.msgid.link/20260608-hdmi-max-bpc-fix-v1-0-6e8dcebc7274@collabora.com --- Nicolas Frattaroli (2): drm/display: hdmi: Only allow BPC values of 8, 10, 12 and 16 drm/display: hdmi: Round odd max_bpc down to even numbers drivers/gpu/drm/display/drm_hdmi_state_helper.c | 12 +++- drivers/gpu/drm/tests/drm_hdmi_state_helper_test.c | 71 ++++++++++++++++++++++ 2 files changed, 82 insertions(+), 1 deletion(-) --- base-commit: 24209d838338d162bb25aadfd637b11747a357ca change-id: 20260608-hdmi-max-bpc-fix-703019763834 Best regards, -- Nicolas Frattaroli