From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 0CE5ABA3F for ; Thu, 9 Oct 2025 12:51:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760014285; cv=none; b=KC9y+I+D95B6yhB5iFKRFGeSH4KgAbhzbGatHaFDUet1z7whiqie++/NH+zS9C7p23YhPGb0OO5euaJMJ9AmYvb3+ZXy2Du28U+FA+/Xzenpn+6KzhiehSziFvkQwQZsg4qLAaWbS/2IiF+m7p3frsA4FPdiM+vBrvCD80hFAbo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760014285; c=relaxed/simple; bh=L2lYR67yrdmGoAFNwPBlzuhg9P5hTiQEPES1NfSMUVk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=G4nMDuvzrtT+/4s73U6CRPjaRkmUmeUDQeLyEI/b8s23FQwJ607UYmyV/btUpc645rvpG6ZW9ddgH63DzyAkFPYqjEdjSc7ILoTHEkGu1NbsOMKZuCSYtRRHdNuMko16WI3/5RfgPaUPL7rudfv89QZhP/p0HRqB10s21TNNp58= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F3C51176A; Thu, 9 Oct 2025 05:51:14 -0700 (PDT) Received: from [10.1.34.29] (e122027.cambridge.arm.com [10.1.34.29]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E0CA93F66E; Thu, 9 Oct 2025 05:51:20 -0700 (PDT) Message-ID: Date: Thu, 9 Oct 2025 13:51:19 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/panthor: Ensure MCU is disabled on suspend To: Boris Brezillon 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 References: <20251008105112.4077015-1-ketil.johnsen@arm.com> <20251009134544.4502df0d@fedora> From: Steven Price Content-Language: en-GB In-Reply-To: <20251009134544.4502df0d@fedora> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 09/10/2025 12:45, Boris Brezillon wrote: > 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. Yeah, at the very least it won't do any harm. I'll add a: Fixes: 2718d91816ee ("drm/panthor: Add the FW logical block") And merge this to drm-misc-fixes. Thanks, Steve