From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 2574735AC05; Wed, 22 Jul 2026 14:56:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784732193; cv=none; b=ATG+7v8OhRgvXmogW7p2S8MVGnvG2cgyB7b4tlSbT2hKcmdtxD5AzwQjuoFG6buD3Gzy6y0hmQu+0xLRIveUJN2RwShNZNbGMM6wa6gK7io6p5J+QYPCecZEvpc24LF33zi3duiu8HX/Pv2B3CgSncNBsUGOq+hgyPEFrrUyq2U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784732193; c=relaxed/simple; bh=CgSzGmAS+QRkLE0LdoH5pWM/VAz+zCNRzPQbraP67jo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kS4kUaCUKf2oL+GJeRGmMp1ENZFHrIUPxVKejNqXDvsAvZXdyLS1cuZEnCIZ+9FNAflJUJ0dQjoSzfW9O8+YG/8oWAXnbjtFaN4Ag1GH06XEAPVRl8AlMF7/cqmOY4nv+a/psRXNFuoF5rZnm/Qqa9jnL3WCSyPhtDA3XrdUivU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MBUeYIi+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MBUeYIi+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96FFA1F000E9; Wed, 22 Jul 2026 14:56:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784732191; bh=v3WvHmJHIPHHvilRXLurOwmXE4QbZCzmkt98mJHIKGk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=MBUeYIi+xsKWeCJ5Siiz8Rog7qRh2ySH/mPwhQphhpn8M998p9D3EeGnn1QCF8M2B JhfMTsvKfumE7v+urYqAdjiXRWabQX3GeE2uHGhDcSA4LPVd/tM+xwhjhdKH5OXeUt +uNM6Io8k5RI/465E45x/gGemcq13buJ271BYuN+9/cyU0iaBa8XLp8MfOSxO4Lsku 11i7Bd3Lz7YxsB7gPwM3oJXFKag3jIZcpvESvXLuiQi0KGIxCGA3O9rjDQOYZSRF+k 3GolkA/7hiZzkA5bPMNZjVAwJpFYWStvIiI0ECjDko9+vyqEgtIXioUs/hJhc8reBf v7I4abrySspHA== Date: Wed, 22 Jul 2026 09:56:30 -0500 From: Bjorn Helgaas To: "Grumbach, Emmanuel" Cc: "sashiko-reviews@lists.linux.dev" , "linux-pci@vger.kernel.org" Subject: Re: [PATCH] PCI: Disable NoSnoop and Relaxed ordering for Intel wireless BE200 Message-ID: <20260722145630.GA729605@bhelgaas> References: <20260621065451.21650-1-emmanuel.grumbach@intel.com> <20260621071242.B20F31F000E9@smtp.kernel.org> <29e347a8ed29e7fdc52ddba72c8ce9da80239993.camel@intel.com> 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: <29e347a8ed29e7fdc52ddba72c8ce9da80239993.camel@intel.com> On Sun, Jun 21, 2026 at 07:30:25AM +0000, Grumbach, Emmanuel wrote: > On Sun, 2026-06-21 at 07:12 +0000, sashiko-bot@kernel.org wrote: > > Thank you for your contribution! Sashiko AI review found 1 potential > > issue(s) to consider: > > - [High] Missing suspend/resume fixup hook for Intel BE200 PCIe > > erratum workaround > > -- > > > > commit ebcdab6d68a92d23aa6cf1713e8e72d87f0e6279 > > Author: Emmanuel Grumbach > > > > PCI: Disable NoSnoop and Relaxed ordering for Intel wireless BE200 > > > > This commit disables NoSnoop and Relaxed ordering on the root port > > for the > > Intel wireless BE200 device because it fails to copy TLP Attributes > > from a > > Request to the Completion. > > > > > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > > > --- a/drivers/pci/quirks.c > > > +++ b/drivers/pci/quirks.c > > > @@ -4674,6 +4674,13 @@ static void > > > quirk_chelsio_T5_disable_root_port_attributes(struct pci_dev *pdev) > > >  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CHELSIO, PCI_ANY_ID, > > >   > > > quirk_chelsio_T5_disable_root_port_attributes); > > >   > > > +/* > > > + * The Intel wireless BE200 fails to copy TLP Attributes from a > > > Request to the > > > + * Completion it generates. > > > + */ > > > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x272b, > > > + quirk_disable_root_port_attributes); > > > > [Severity: High] > > Will this workaround survive a system suspend and resume cycle? > > > > When the Intel BE200 device is hotplugged, the upstream Root Port's > > configuration state is saved at boot time by pcie_portdrv_probe(), > > which calls pci_save_state(). The workaround modifies the Root Port's > > current configuration to disable Relaxed Ordering and No Snoop, but it > > does not update the Root Port's saved state array. > > That's a good point, but I'm not sure we really test well hotplug... It looks like BE200 is normally an M.2 form factor, and I don't think M.2 is designed to support hotplug. I guess it could be done with an M.2-to-PCIe adapter, but that seems a bit esoteric. > > Upon system suspend, the PCI core skips saving the Root Port's state > > because its state_saved flag is already true. During resume, > > pci_restore_state() restores the Root Port to its original boot-time > > state, which would re-enable the problematic attributes. > > > > Should there also be a DECLARE_PCI_FIXUP_RESUME_EARLY hook registered > > here to ensure the workaround is re-applied when the device resumes? I'm pretty sure the header quirks would be run before portdrv probes, so I guess this is part of the same theoretical scenario, where portdrv probes before a BE200 is hot-added. Can we include any relevant dmesg output, e.g., AER errors or whatever motivated this quirk in the first place? c56d4450eb68 ("PCI: Turn off Request Attributes to avoid Chelsio T5 Completion erratum") mentions Malformed TLP or Unexpected Completion errors, so I suppose this is similar?