From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (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 351212C15A0 for ; Thu, 9 Oct 2025 11:45:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760010353; cv=none; b=shDIpPqC6psbTQPoZfRSA5kyZ6q4KTdEDSb8w3ui4sCtzinl0V3oeKROIOFH/OEGErnFI8LxoVshD7kdo/flwpgez7jma3qYVNdU7Xrdv+qvX/jQdAPo5DzWHSKO133oeeHbBwX7ZYMsU0NY6dgsPsYlqzLMFR5Nc/X+0G9b0so= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760010353; c=relaxed/simple; bh=ydT5M4LU+rhLL79QpjncBuMwrnRWUgqtMFqnfSJgBRw=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=XKbivuydYtt9qQcdA+hAqcJALf9Nkt2OlC3OiWkZFzkcWpn2dLNMzkUMqqHBZnlSgweW4FUfglOekUXyWxQ8l7vNTfKaeRZHrtgC32mXhwWkcD51CANWN2uN01I63x7fVDd6rNd+ueKO1RFHezo5fCdd4cys72P0MdlaojSzO4w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=D1dYW+iF; arc=none smtp.client-ip=148.251.105.195 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 (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="D1dYW+iF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1760010349; bh=ydT5M4LU+rhLL79QpjncBuMwrnRWUgqtMFqnfSJgBRw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=D1dYW+iFyJHdB/WD4vXVwQlfkHSZtxoPucqlTsL3NmAsg/U+0MDRzaxpt+hkytQk0 i6JGmp5SurPLwdqlLCZgCmbimiplgLa0y+BgKtKJBNXXBD6B+laBPDTV9+6A3QbEi3 pq9tJNTiRQokJ6uICuzIPRTChCx5b1RFg0ZfmJWRXLEk5N6mlwENoB0Yf/KRJLONRv IthPBSH9EYMqesv4Y2vNTFL/GJHLJg1xyfT+F+FRH64Ci0wHJVG0VN1UlhfmExplIQ 6pqSfz6y/W9MqmzWdkKaIReMNrzChuyHR690AfCAp1gPEQGNlbj1O/9VxiYrQRhPZX hH8VbgLCMK1uA== Received: from fedora (unknown [IPv6:2a01:e0a:2c:6930:d919:a6e:5ea1:8a9f]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by bali.collaboradmins.com (Postfix) with ESMTPSA id 00A5F17E1060; Thu, 9 Oct 2025 13:45:48 +0200 (CEST) Date: Thu, 9 Oct 2025 13:45:44 +0200 From: Boris Brezillon To: Steven Price Cc: Ketil Johnsen , Liviu Dudau , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/panthor: Ensure MCU is disabled on suspend Message-ID: <20251009134544.4502df0d@fedora> In-Reply-To: References: <20251008105112.4077015-1-ketil.johnsen@arm.com> Organization: Collabora X-Mailer: Claws Mail 4.3.1 (GTK 3.24.49; x86_64-redhat-linux-gnu) 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=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 9 Oct 2025 11:29:14 +0100 Steven Price wrote: > On 08/10/2025 11:51, Ketil Johnsen wrote: > > Currently the Panthor driver needs the GPU to be powered down > > between suspend and resume. If this is not done, then the > > MCU_CONTROL register will be preserved as AUTO, which again will > > cause a premature FW boot on resume. The FW will go directly into > > fatal state in this case. > > > > This case needs to be handled as there is no guarantee that the > > GPU will be powered down after the suspend callback on all platforms. > > > > The fix is to call panthor_fw_stop() in "pre-reset" path to ensure > > the MCU_CONTROL register is cleared (set DISABLE). This matches > > well with the already existing call to panthor_fw_start() from the > > "post-reset" path. > > > > Signed-off-by: Ketil Johnsen > > Reviewed-by: Steven Price > > Do we need a Fixes tag? Or is this only actually an issue on newer GPUs? I think it'd be good to have a Fixes tag, if it's known to be the right thing to do after a HALT, even if it's not needed on the GPUs currently supported by this driver.