From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7B5C97443C; Wed, 28 Feb 2024 22:02:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709157737; cv=none; b=iMQTqX0ledwy51TUvWow4iHwitZSt1cj8Nj5zPJWDhRTLZxYe7/9m2jEy534/GiA3tbrBbgHEmVGsZtGWOSzg67etAx/7PTjCuI47HR2ctrHytWCrqEdF+LzEZykamV+PG5hwIwwqkGHcktzMcom3Q+28336QPieYHufmO2ueCI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709157737; c=relaxed/simple; bh=gPOdghli+9QBbrWalwVFo9yVmHQwrDvufi1/D3sjuJU=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=dwHUWGupJSIrr9j6MdQD7UpnUMBSSoc1xn1fGwQtN3cWIjxY7Yxi6wgO0/1H4NY3TvZAlILDCGkpg//KgWe2NvklJqdRSJ9mO2yFov+L9wLZgxSS8zcYes+1yYHJxL5Fd4o+Co+moqk5FMN6N7VvgYcziCUYdphxYhDziwtn/8A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mSjD+Abf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mSjD+Abf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7408C433F1; Wed, 28 Feb 2024 22:02:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709157737; bh=gPOdghli+9QBbrWalwVFo9yVmHQwrDvufi1/D3sjuJU=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=mSjD+AbfYXIBYbQ4bhnujqShmhMYIuSgeohNkRNuEha5uRrMMtmh9NSmoiBkanSSH pzx8U1uk4eCfRXmGj1u0D82Vr61lA7o1701VRvmrp5NAH7K15iRBqu2rPYVQnqKTKt OF0S37fJftNMBe0q+Rbv6zdrP1F7B9TMwICmtuwKp0c3uhNactpNOtSwB0QRI17zTR 4083jOeCzOzVgFyWsK9i124ivPvp5QbClQ6grbp3rAyQXGLg9Z+oveKbkEnZNaiIzp dS47NLmnygDe4Ue9p+AyQGTBEJtDVbdHv9G9TJ18ghN679o6bUt0+L6ugQWdZEvT0w QTTfj64E6EjbA== Date: Wed, 28 Feb 2024 16:02:15 -0600 From: Bjorn Helgaas To: Johan Hovold Cc: Johan Hovold , Bjorn Helgaas , Bjorn Andersson , Konrad Dybcio , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Manivannan Sadhasivam , linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v2 04/12] PCI: qcom: Add support for disabling ASPM L0s in devicetree Message-ID: <20240228220215.GA308296@bhelgaas> Precedence: bulk X-Mailing-List: devicetree@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: On Tue, Feb 27, 2024 at 04:29:15PM +0100, Johan Hovold wrote: > On Fri, Feb 23, 2024 at 04:10:00PM -0600, Bjorn Helgaas wrote: > > On Fri, Feb 23, 2024 at 04:21:16PM +0100, Johan Hovold wrote: > > > Commit 9f4f3dfad8cf ("PCI: qcom: Enable ASPM for platforms supporting > > > 1.9.0 ops") started enabling ASPM unconditionally when the hardware > > > claims to support it. This triggers Correctable Errors for some PCIe > > > devices on machines like the Lenovo ThinkPad X13s, which could indicate > > > an incomplete driver ASPM implementation or that the hardware does in > > > fact not support L0s. > > > > Are there any more details about this? Do the errors occur around > > suspend/resume, a power state transition, or some other event? Might > > other DWC-based devices be susceptible? Is there a specific driver > > you suspect might be incomplete? > > I see these errors when the devices in question are active as well as > idle (not during suspend/resume). For example, when running iperf3 or > fio to test the wifi and nvme, but I also see this occasionally for a > wifi device which is (supposedly) not active (e.g. a handful errors over > night). > > I skimmed Qualcomm's driver and noted that there are some registers > related to ASPM which that driver updates, while the mainline driver > leaves them at their default settings, but I essentially only mentioned > that the ASPM implementation may be incomplete as a theoretical > possibility. The somewhat erratic ASPM behaviour for one of the modems > also suggests that some further tweak/quirk may be needed, and I was > hoping to catch Mani's interest by reporting it. > > But based on what I've since heard from Qualcomm, it seems like these > correctable error may be a known issue with the hardware (e.g. seen > also with Windows), which is also why we decided to disable it for all > controllers on these two platforms where I've seen this in v2. > > > Do you want the DT approach because the problem is believed to be > > platform-specific? Otherwise, maybe we should consider reverting > > 9f4f3dfad8cf until the problem is understood? > > Enabling ASPM gave a very significant improvement in battery life on the > Lenovo ThinkPad X13s, from 10.5 h to 15 h, so reverting is not really an > option there. Ah, I missed that you're only disabling L0s, but leaving L1 enabled, thanks! And given that the v1.9.0 ops that enable ASPM are used on a bunch of platforms, and L0s seems to work fine on most of them, we wouldn't want to disable L0s for everybody, so this seems like the right solution. Bjorn