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 D5FD7309EE9; Fri, 6 Feb 2026 22:59:06 +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=1770418746; cv=none; b=Fj94aGGtE8mCxs3MVI0nooLuTAerFPZoQKewClSXih5EgOPkZ0EE9cQPbpkQMOHv5nrE+MGDPVB4KYCq/GNKp8hRn8W4UNCcFI6P7cQqGyOVExtm7n9/NjxU7PC4ZYBiMRw3N1Jv4KXO1mOsoUPWYKyQD7w18DF8Bde+QOrSnpo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770418746; c=relaxed/simple; bh=79gUol5oeNcxMoawxQyWlDCHIdz7vTlXoRbNh+iyTJU=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=td/hJyDNdWzfovzisGy/ArPwTcDUPux/wHcnIhtJUNj8o36C/R0/UV6qANVtLCOkAXarDxtNmpZz0RIGRFFZ1BdBOSe/0uPsaie8d8fpRU+cIqfalu3n1SWHUpt8vxECLglY0u727aNJ2mZLOEZQUe/6Wvrz3RSvDzpemFOeruk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pnOBHWi+; 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="pnOBHWi+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F4E8C116C6; Fri, 6 Feb 2026 22:59:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770418746; bh=79gUol5oeNcxMoawxQyWlDCHIdz7vTlXoRbNh+iyTJU=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=pnOBHWi+IDzNqmI/qp00vvOe6AI6lggVmBRXUNbnd2La57yxpUNP07QwHXETHodEJ fIK1WQdhqAsunekuF0cZJzwOTahENbnhejycYhaAIblS+cMGRsoWYc28gyI56cJltL 0VZ8fSmNYs1//eCHPHsHjMjGUOG4MboLUTInlMFto59Du53LAWgw23EkxDeCjqUDTH l8ZxXujfoClyZmVRHNxxEJqYPO9bqwMM5nfJQvh5ZNVGJO/P8WwkCQzjsNrVMfb2aP fBE2FSiRziwmqkGnYvPfpAWbUal+l0tJ/hFOvYl+PzrNUkgcBLY+WHXTuueJHM8Iq6 EM1ze3qK+XNSQ== Date: Fri, 6 Feb 2026 16:59:05 -0600 From: Bjorn Helgaas To: Ilpo =?utf-8?B?SsOkcnZpbmVu?= Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Adam Stylinski Subject: Re: [PATCH 1/1] PCI/bwctrl: Disable BW controller on Intel P45 using a quirk Message-ID: <20260206225905.GA103793@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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260116131513.2359-1-ilpo.jarvinen@linux.intel.com> On Fri, Jan 16, 2026 at 03:15:12PM +0200, Ilpo Järvinen wrote: > The commit 665745f27487 ("PCI/bwctrl: Re-add BW notification portdrv as > PCIe BW controller") was found to lead to a boot hang on a Intel P45 > system. Testing without setting Link Bandwidth Management Interrupt > Enable (LBMIE) and Link Autonomous Bandwidth Interrupt Enable (LABIE) > (PCIe r7.0, sec. 7.5.3.7) in bwctrl allowed system to come up. > > P45 is very old chipset and supports only up to gen2 PCIe, so not > having bwctrl does not seem a huge defiancy. > > Add no_bw_notif into the struct pci_dev and quirk Intel P45 Root Port > with it. > > Reported-by: Adam Stylinski > Link: https://lore.kernel.org/linux-pci/aUCt1tHhm_-XIVvi@eggsbenedict/ > Tested-by: Adam Stylinski > Signed-off-by: Ilpo Järvinen Applied to pci/bwctrl for v6.20, thanks! > --- > drivers/pci/pcie/bwctrl.c | 3 +++ > drivers/pci/quirks.c | 10 ++++++++++ > include/linux/pci.h | 1 + > 3 files changed, 14 insertions(+) > > diff --git a/drivers/pci/pcie/bwctrl.c b/drivers/pci/pcie/bwctrl.c > index 36f939f23d34..4ae92c9f912a 100644 > --- a/drivers/pci/pcie/bwctrl.c > +++ b/drivers/pci/pcie/bwctrl.c > @@ -250,6 +250,9 @@ static int pcie_bwnotif_probe(struct pcie_device *srv) > struct pci_dev *port = srv->port; > int ret; > > + if (port->no_bw_notif) > + return -ENODEV; > + > /* Can happen if we run out of bus numbers during enumeration. */ > if (!port->subordinate) > return -ENODEV; > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index b9c252aa6fe0..6ef42a2c4831 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -1359,6 +1359,16 @@ static void quirk_transparent_bridge(struct pci_dev *dev) > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82380FB, quirk_transparent_bridge); > DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_TOSHIBA, 0x605, quirk_transparent_bridge); > > +/* > + * Enabling Link Bandwidth Management Interrupts (BW notifications) can cause > + * boot hangs on P45. > + */ > +static void quirk_p45_bw_notifications(struct pci_dev *dev) > +{ > + dev->no_bw_notif = 1; > +} > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2e21, quirk_p45_bw_notifications); > + > /* > * Common misconfiguration of the MediaGX/Geode PCI master that will reduce > * PCI bandwidth from 70MB/s to 25MB/s. See the GXM/GXLV/GX1 datasheets > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 864775651c6f..3a556cd749e3 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -406,6 +406,7 @@ struct pci_dev { > user sysfs */ > unsigned int clear_retrain_link:1; /* Need to clear Retrain Link > bit manually */ > + unsigned int no_bw_notif:1; /* BW notifications may cause issues */ > unsigned int d3hot_delay; /* D3hot->D0 transition time in ms */ > unsigned int d3cold_delay; /* D3cold->D0 transition time in ms */ > > > base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8 > -- > 2.39.5 >