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 8C05923AE87; Mon, 15 Dec 2025 06:47:36 +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=1765781256; cv=none; b=F1Wt+icRPSgMVN6YbiIPu6OfnyACqKMbAd4lHZ1bU/0/b7etKJukEM7qap7s1q1VVKOsW+jTO83PqmTa65UIJ1v1WsivKuSJYsKpgwuMHvewN3/spp6jT5WysDFcwEplEuXZjyNArYgXJ+fE4k1KLHCvYeb/luMIi7Q14nqJLKE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765781256; c=relaxed/simple; bh=QbZDeielAT/7MonO7SqhnIm+38TaXu7Dq5ciEvhzlY8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=uSzwii9qMuq4jPcAxN0QruTS2aqy8Ni6hee6262zURE7+PjeNWLc0gdWVeS+NVOGl4VEO7kjibZYmIpzCIb2t6u6AvoYgv2LzHkIVavjpSrKeg40NUtsBb1UFpFXk5dTH1FZ1HB5vtBSbb9dWysHEOof/vpfV94CCPNzJaEAb88= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KJyvko0C; 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="KJyvko0C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 677AAC4CEF5; Mon, 15 Dec 2025 06:47:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765781256; bh=QbZDeielAT/7MonO7SqhnIm+38TaXu7Dq5ciEvhzlY8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=KJyvko0Colmzf5Gf6FPfhYg12bw3bDKLEtlA3Zb1ZYXPLQPkVwUge+jCtRSHBDd7+ h9IPchKq+tlfP8CE1rJzLQWTdtrXPpexBgN33AQKCOzcbz6sh4u+orWk3cdT5CYuSY 8ObRKC25SvqFm58gX49GOUGsYE49GMu0WYIwTcVYZuPe9Ae608TXzakKZ4GRsLSyYb +1XSQJr9nR92BXrsR1YtFmJzK4BVy3PZYJDPihG+w8FcCmX6fgNJ8J5SnPGD935LB+ ZPtOBjLnUdveHbYopOdK1wsnTtLOz19eZFWdHsT+l6VmI9AHGNmA/ZeOj1H0oq49r2 TQmGT5RA2xDwg== Message-ID: Date: Mon, 15 Dec 2025 15:47:34 +0900 Precedence: bulk X-Mailing-List: linux-ide@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [REGRESSION] libata: SATA LPM forcibly disabled on Intel Jasper Lake since Linux 6.13 To: Bernard Drozd , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Niklas Cassel References: <635cb04f-eda3-49ec-b8bc-62f4e8c7926f@interia.pl> <37a2d604-6c20-4913-ad1a-15e727df8a3d@kernel.org> Content-Language: en-US From: Damien Le Moal Organization: Western Digital Research In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 12/15/25 13:28, Bernard Drozd wrote: > Hi Damien, > Thank you for the explanation – I understand now that pre-6.13 behaviour > was relying on a bug allowing userspace to override unsupported LPM. > I have collected full diagnostics comparing a *working* kernel (6.12) > and a *regressed* kernel (6.17), both tested with **no SATA devices > connected**. > > Important correction: > The correct SATA controller PCI ID is: > Intel Jasper Lake SATA AHCI Controller [8086:4dd3] > This was mistakenly reported earlier as 4d03. > > Key observation: > The LPM disable happens even with no SATA devices attached, so this > appears to be a **platform-level decision**, not device capability. > > Data provided: > 1) Full dmesg, Linux 6.12 (LPM works, CPU reaches PC10): > https://www.dropbox.com/scl/fi/pwc0bfgoqgb607babczg9/dmesg-6.12-full.txt?rlkey=o8j88lzeq3rw3cbx2q65oyblv&st=u4dwqv0p&raw=1 > > 2) Full dmesg, Linux 6.17 (LPM forced to max_performance, CPU stuck in PC2): > https://www.dropbox.com/scl/fi/twbyjm7h5ewgmllit02h8/dmesg-6.17-full.txt?rlkey=p3b97lli6ruo5ypg4c2d4jnc2&st=3o3xo47m&raw=1 Got it: your AHCI adapter has: ahci 0000:00:17.0: AHCI vers 0001.0301, 32 command slots, 6 Gbps, SATA mode ahci 0000:00:17.0: 2/2 ports implemented (port mask 0x3) ahci 0000:00:17.0: flags: 64bit ncq sntf pm led clo only pio slum part deso sadm sds Partial and slumber are supported, so all good. BUT ! your ports are... ata1: SATA max UDMA/133 abar m2048@0x80102000 port 0x80102100 irq 142 lpm-pol 1 ext ata2: SATA max UDMA/133 abar m2048@0x80102000 port 0x80102180 irq 142 lpm-pol 1 ext ...external. That is, the adapter is saying that these are external/hot-pluggable ports, and for these, power management is a bad idea/should be disabled, which we do. The reason is that otherwise, we cannot catch hot-plug/unplug events (IRQs). So to enable low-power policies, you need to go into your BIOS settings and disable the hot-plugging capability for the ports. Many BIOSes have such setting for SATA ports. If your BIOS does not have this, yu can use the mask_port_ext AHCI module parameter. Simply add: ahci.mask_port_ext=0x3 to your kernel command line and the "ext" flag of the ports will be ignored and LPM enabled. -- Damien Le Moal Western Digital Research