From nobody Sat Feb 7 17:20:34 2026 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 441D534B1AE; Thu, 23 Oct 2025 18:07:00 +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=1761242821; cv=none; b=GGNKHZpx7ZUzxxus8cd9h9G9sRPX3NEObjYN5oDSOteq14Nfk9Wm4zBQ5NtIGLHYW88EUaHcTexzc1cTomWg3czpu4QL5gdJlMlMGa57MSuP8cpK2FKLknQ2OgS7tTKoENrcNRkpamCNXFJHC+SBneTuR6/8SyjBDoo7uEIcduY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761242821; c=relaxed/simple; bh=b5POU65SI9uBItwU3VrQQapA5Fe5zoNWbwcZVbOTXlo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=gBP4w9F5FgQ/zsjcJwrl2GSA4/WSC9VQUtvYaS5J9wVgPFwT//K5tE9q3p9nwno9apQyg0g++965dlYbH4+4l7rifeY7Dg7tbRbgKDK3Jpp9JqfUf1nb8iWHH4OHnBC/UEeATRDoFuiX29TrTQ6R16oeGjn8VXdV4NxEC63XNkE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=V5Z6NbT6; 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="V5Z6NbT6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1A93C4CEE7; Thu, 23 Oct 2025 18:07:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761242820; bh=b5POU65SI9uBItwU3VrQQapA5Fe5zoNWbwcZVbOTXlo=; h=From:To:Cc:Subject:Date:From; b=V5Z6NbT6+ZsvBawxRtQxU7LhzI9ILCHAXbufohmEyU04NEMevBNBjSTSRUOGz0Q6M p/J8OXFmnNBJwV8Z7CvorFLum3GOtQkbxP5iqmU671wwUKwqgVNcwVxXHQ/0ddSG4/ WnyzlBLS4VlcV8QXxN57mSobGCvmXQUwTGjRneEg77O9umCvyPvHMWxlpsskxpr05i A7EwOXDh3hCDu9JbL1yuX8Zlf41V1lduTmNA4AFpT5PMbdfqRgb0/x7IebHpC7K8Vc xzrTrxOAdhXbQg4kmhjO0yEukjIjPBOAvhN0Q9GtFiCHbacF6o9UEmjW0D+0iLFXg7 W7Yne6d0AMhiA== From: Bjorn Helgaas To: linux-pci@vger.kernel.org Cc: Manivannan Sadhasivam , Christian Zigotzky , FUKAUMI Naoki , Herve Codina , Diederik de Haas , Dragan Simic , linuxppc-dev@lists.ozlabs.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org, Bjorn Helgaas Subject: [PATCH] PCI/ASPM: Enable only L0s and L1 for devicetree platforms Date: Thu, 23 Oct 2025 13:06:26 -0500 Message-ID: <20251023180645.1304701-1-helgaas@kernel.org> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Bjorn Helgaas f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devicetree platforms") enabled Clock Power Management and L1 PM Substates, but those features depend on CLKREQ# and possibly other device-specific configuration. We don't know whether CLKREQ# is supported, so we shouldn't blindly enable Clock PM and L1 PM Substates. Enable only ASPM L0s and L1, and only when both ends of the link advertise support for them. Fixes: f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devi= cetree platforms") Reported-by: Christian Zigotzky Link: https://lore.kernel.org/r/db5c95a1-cf3e-46f9-8045-a1b04908051a@xenoso= ft.de/ Reported-by: FUKAUMI Naoki Closes: https://lore.kernel.org/r/22594781424C5C98+22cb5d61-19b1-4353-9818-= 3bb2b311da0b@radxa.com/ Reported-by: Herve Codina Link: https://lore.kernel.org/r/20251015101304.3ec03e6b@bootlin.com/ Reported-by: Diederik de Haas Link: https://lore.kernel.org/r/DDJXHRIRGTW9.GYC2ULZ5WQAL@cknow-tech.com/ Signed-off-by: Bjorn Helgaas Tested-by: FUKAUMI Naoki Acked-by: Dragan Simic Tested-by: Diederik de Haas --- I intend this for v6.18-rc3. I think it will fix the issues reported by Diederik and FUKAUMI Naoki (both on Rockchip). I hope it will fix Christian's report on powerpc, but don't have confirmation. I think the performance regression Herve reported is related, but this patch doesn't seem to fix it. FUKAUMI Naoki's successful testing report: https://lore.kernel.org/r/4B275FBD7B747BE6+a3e5b367-9710-4b67-9d66-3ea34fc3= 0866@radxa.com/ --- drivers/pci/pcie/aspm.c | 34 +++++++++------------------------- 1 file changed, 9 insertions(+), 25 deletions(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 7cc8281e7011..79b965158473 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -243,8 +243,7 @@ struct pcie_link_state { /* Clock PM state */ u32 clkpm_capable:1; /* Clock PM capable? */ u32 clkpm_enabled:1; /* Current Clock PM state */ - u32 clkpm_default:1; /* Default Clock PM state by BIOS or - override */ + u32 clkpm_default:1; /* Default Clock PM state by BIOS */ u32 clkpm_disable:1; /* Clock PM disabled */ }; =20 @@ -376,18 +375,6 @@ static void pcie_set_clkpm(struct pcie_link_state *lin= k, int enable) pcie_set_clkpm_nocheck(link, enable); } =20 -static void pcie_clkpm_override_default_link_state(struct pcie_link_state = *link, - int enabled) -{ - struct pci_dev *pdev =3D link->downstream; - - /* For devicetree platforms, enable ClockPM by default */ - if (of_have_populated_dt() && !enabled) { - link->clkpm_default =3D 1; - pci_info(pdev, "ASPM: DT platform, enabling ClockPM\n"); - } -} - static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklis= t) { int capable =3D 1, enabled =3D 1; @@ -410,7 +397,6 @@ static void pcie_clkpm_cap_init(struct pcie_link_state = *link, int blacklist) } link->clkpm_enabled =3D enabled; link->clkpm_default =3D enabled; - pcie_clkpm_override_default_link_state(link, enabled); link->clkpm_capable =3D capable; link->clkpm_disable =3D blacklist ? 1 : 0; } @@ -811,19 +797,17 @@ static void pcie_aspm_override_default_link_state(str= uct pcie_link_state *link) struct pci_dev *pdev =3D link->downstream; u32 override; =20 - /* For devicetree platforms, enable all ASPM states by default */ + /* For devicetree platforms, enable L0s and L1 by default */ if (of_have_populated_dt()) { - link->aspm_default =3D PCIE_LINK_STATE_ASPM_ALL; + if (link->aspm_support & PCIE_LINK_STATE_L0S) + link->aspm_default |=3D PCIE_LINK_STATE_L0S; + if (link->aspm_support & PCIE_LINK_STATE_L1) + link->aspm_default |=3D PCIE_LINK_STATE_L1; override =3D link->aspm_default & ~link->aspm_enabled; if (override) - pci_info(pdev, "ASPM: DT platform, enabling%s%s%s%s%s%s%s\n", - FLAG(override, L0S_UP, " L0s-up"), - FLAG(override, L0S_DW, " L0s-dw"), - FLAG(override, L1, " L1"), - FLAG(override, L1_1, " ASPM-L1.1"), - FLAG(override, L1_2, " ASPM-L1.2"), - FLAG(override, L1_1_PCIPM, " PCI-PM-L1.1"), - FLAG(override, L1_2_PCIPM, " PCI-PM-L1.2")); + pci_info(pdev, "ASPM: default states%s%s\n", + FLAG(override, L0S, " L0s"), + FLAG(override, L1, " L1")); } } =20 --=20 2.43.0