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 3E1E43161BC for ; Wed, 15 Oct 2025 23:41:01 +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=1760571661; cv=none; b=K0pbl3a/g3vmC9tD2s940aQgD18IWkUJF1FJRPkEso8cul7w84ovAuUIKpdYtDDEBLlVb/YkAz1bgpk3zueFTaV9dxdfLUuExYCLWpke7ELtrvbm/G3hxOIyLCSYRljXd83k12wXD6M8uu1/J6Wzq+SQyn6IUCcLm3wepkbvgbE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760571661; c=relaxed/simple; bh=7ZVXV77W0d05bk/8gSWIHFEpHIZsQ9H36dwcXGXNqro=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=Zf21aPn/H3itNnbOwZQQ0LpQImOP2f/tojWub2Fq5Zekem4QsoZMQdmFfBEee7yO/U8ZMR1Upp9Hd+1bgtA694niAXitUKB+LAc/XxdzAcc8liUQeiSsgrbx8f0DDFlH4XVjwdwjcaabPk2Bopvdjpbcg94grsN+RbbspPPsYs4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=h3+qsstL; 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="h3+qsstL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E89F1C4CEF8; Wed, 15 Oct 2025 23:41:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760571661; bh=7ZVXV77W0d05bk/8gSWIHFEpHIZsQ9H36dwcXGXNqro=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=h3+qsstLdZgrMKrIYjUUZJ3SpvHx3e+0csZghHbFI8vZbxfVK/12Zf+LUjJPRCy6Y pohFdY1HaBTMKdKHwutLvPO+PtHZB0hLTuyDrsWj/t7xUmSLjNJjHNT0I2ZIhtDR+u SNCw6SfnHhStgY9NVmZSJANBBGWFHP/KPTU71RmsroxJA8pWIrmyakAMOGhd0gRKGH 5GqgIy5P0cM1GHzA/SrSJOh3mhTWiqAJSqeKl1fAE45R/L4uXugJaIhti/x6XFG7Eu hCtg7UOPklPh/aO/TMXEk16iIYXrlwCfDfrjc+TAsQ/fv5Lsk8bp2yBVAQBsIKmwzi MA/Cqt6Jnyc+g== Date: Wed, 15 Oct 2025 18:40:59 -0500 From: Bjorn Helgaas To: Herve Codina Cc: Manivannan Sadhasivam , Lukas Wunner , Christian Zigotzky , Manivannan Sadhasivam , Ilpo =?utf-8?B?SsOkcnZpbmVu?= , "linux-pci@vger.kernel.org" , mad skateman , "R.T.Dickinson" , Christian Zigotzky , linuxppc-dev , hypexed@yahoo.com.au, Darren Stevens , "debian-powerpc@lists.debian.org" , Thomas Petazzoni Subject: Re: [PPC] Boot problems after the pci-v6.18-changes Message-ID: <20251015234059.GA961901@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@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: <20251015101304.3ec03e6b@bootlin.com> On Wed, Oct 15, 2025 at 10:13:04AM +0200, Herve Codina wrote: > ... > I also observed issues with the commit f3ac2ff14834 ("PCI/ASPM: Enable all > ClockPM and ASPM states for devicetree platforms") > > My system is an ARM board (Marvel Armada 3720 DDB) > https://elixir.bootlin.com/linux/v6.17.1/source/arch/arm64/boot/dts/marvell/armada-3720-db.dts > > I use an LAN966x PCI board > https://elixir.bootlin.com/linux/v6.17.1/source/drivers/misc/lan966x_pci.c > > Usually, when I did a ping using the PCI board, I have more or less the > following timings: > # ping 192.168.32.100 > PING 192.168.32.100 (192.168.32.100): 56 data bytes > 64 bytes from 192.168.32.100: seq=0 ttl=64 time=3.328 ms > 64 bytes from 192.168.32.100: seq=1 ttl=64 time=2.636 ms > 64 bytes from 192.168.32.100: seq=2 ttl=64 time=2.928 ms > 64 bytes from 192.168.32.100: seq=3 ttl=64 time=2.649 ms > > But with a vanilla v6.18-rc1 kernel, those timings become awful: > # ping 192.168.32.100 > PING 192.168.32.100 (192.168.32.100): 56 data bytes > 64 bytes from 192.168.32.100: seq=0 ttl=64 time=656.634 ms > 64 bytes from 192.168.32.100: seq=1 ttl=64 time=551.812 ms > 64 bytes from 192.168.32.100: seq=2 ttl=64 time=702.966 ms > 64 bytes from 192.168.32.100: seq=3 ttl=64 time=725.904 ms > > Reverting commit f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and > ASPM states for devicetree platforms") fixes my timing issues. We expect *some* performance impact from enabling ASPM, but this seems excessive. You should be able to control the ASPM settings for an individual device via sysfs: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/ABI/testing/sysfs-bus-pci?id=v6.17-rc1#n431 My guess is that L1.2 is enabled and the threshold values in the L1 PM Substates control registers are bogus. I don't know how to fix those, especially on a devicetree system. But it might be possible to fiddle with them using setpci (while ASPM is disabled). Not for the faint of heart. Bjorn