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 A209E3644AF for ; Thu, 30 Apr 2026 16:54:21 +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=1777568063; cv=none; b=dRHlpMJ6mODtNFhNRgSBDZn7pWhmxtU3Pg26AiBTpUUCTVeXEwBpnU0WBHGZAoWLMUxhBnkpQpWxfPviohWNoaj7pycQuCZFxWHbhwVmnvP7Oltj0J9R89/XUyyyFx7IbyHXUDAnXjTIAVegK9VF4yvWTP5JSkc6HIOF5NxEyK4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777568063; c=relaxed/simple; bh=0aE0e+1TBdahKKaq6tlLRD0Vy8TxtU1tIj610UdY+qw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YEca/W/swXpYp3+6cwTSYFX+ILrMS10lj95c5eOSI1U9TI5VNH4GSsIw7dDtRVdcnwn5cumpj27sS03aIys2ilLJw+xg/ssVS0B93Q6pCsIQCLazg3WYytWL032XiWXqppKXc0edi4evIAK/qFFwNdgiRRp8ZXdkBc02M7nhN8g= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=kJmz3Z+n; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="kJmz3Z+n" 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 51C3F359B; Thu, 30 Apr 2026 09:54:15 -0700 (PDT) Received: from localhost (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5EA6D3F62B; Thu, 30 Apr 2026 09:54:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777568060; bh=0aE0e+1TBdahKKaq6tlLRD0Vy8TxtU1tIj610UdY+qw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kJmz3Z+nrMApGsUU4ly8Mx9Doad2qelaDVd0yRedu6aLq4CRvli4offMkfO6v6Twj 22VN4JFBi0pBI0Sn1bUMiQSQL1YTBIYL7EBJtvSUfDKGlonOZAGWH6LdAGOGx/jnq8 F3371MTuoxQiKYdnMQb0PahR5vN0FBuFp0N2cKnI= Date: Thu, 30 Apr 2026 17:54:18 +0100 From: Leo Yan To: James Clark Cc: Suzuki K Poulose , Mike Leach , Alexander Shishkin , Mathieu Poirier , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] coresight: ete: Always save state on power down Message-ID: <20260430165418.GF16537@e132581.arm.com> References: <20260428-james-cs-ete-pm_save_enable-v1-0-c7a90ca6f43b@linaro.org> <20260428-james-cs-ete-pm_save_enable-v1-1-c7a90ca6f43b@linaro.org> 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-Disposition: inline In-Reply-To: <20260428-james-cs-ete-pm_save_enable-v1-1-c7a90ca6f43b@linaro.org> On Tue, Apr 28, 2026 at 01:18:11PM +0100, James Clark wrote: > ETE registers are always system registers so it's highly unlikely there > will be an implementation that preserves them on CPU power down. Also > the ETE DT binding never documented > "arm,coresight-loses-context-with-cpu" so nobody would have legitimately > been able to use that binding to fix it. > > Fix it by hard coding the setting for ETE and add a warning if the user > tried to use the module parameter. Don't add a warning if > loses-context-with-cpu is present in the DT as it's not a documented > binding anyway. etm4_init_pm_save() needs to happen after drvdata is > initialised so etm4x_is_ete() can be called. > > This fixes the following error when using Coresight with ACPI on the FVP > which supports CPU PM: > > coresight ete0: External agent took claim tag > WARNING: drivers/hwtracing/coresight/coresight-core.c:248 at coresight_disclaim_device_unlocked+0xe0/0xe8, CPU#0: perf/117 > > Fixes: 35e1c9163e02 ("coresight: ete: Add support for ETE tracing") > Signed-off-by: James Clark Reviewed-by: Leo Yan