Return-path: Received: from bues.ch ([80.190.117.144]:41995 "EHLO bues.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751355AbcDBHat (ORCPT ); Sat, 2 Apr 2016 03:30:49 -0400 Date: Sat, 2 Apr 2016 09:30:29 +0200 From: Michael =?UTF-8?B?QsO8c2No?= To: Lukas Wunner Cc: Chris Bainbridge , linux-pci@vger.kernel.org, linux-wireless@vger.kernel.org, b43-dev@lists.infradead.org Subject: Re: [PATCH] PCI: Add Broadcom 4331 reset quirk to prevent IRQ storm Message-ID: <20160402093029.3dc29699@wiggum> (sfid-20160402_093052_852662_A9911E01) In-Reply-To: <20160401224646.GA11281@wunner.de> References: <20160331231346.GA7469@localhost> <20160401224646.GA11281@wunner.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; boundary="Sig_/fzMTu7h3u6MhxX3sAj05oK9"; protocol="application/pgp-signature" Sender: linux-wireless-owner@vger.kernel.org List-ID: --Sig_/fzMTu7h3u6MhxX3sAj05oK9 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sat, 2 Apr 2016 00:46:46 +0200 Lukas Wunner wrote: > Hi Chris, >=20 > On Fri, Apr 01, 2016 at 12:13:46AM +0100, Chris Bainbridge wrote: > > On Tue, Mar 29, 2016 at 07:41:30PM +0200, Lukas Wunner wrote: =20 > > > Broadcom 4331 wireless cards built into Apple Macs unleash an IRQ sto= rm > > > on boot until they are reset, causing spurious interrupts if the IRQ = is > > > shared. Apparently the EFI bootloader enables the device and does not > > > disable it before passing control to the OS. The bootloader contains a > > > driver for the wireless card which allows it to phone home to Cuperti= no. > > > This is used for Internet Recovery (download and install OS X images) > > > and probably also for Back to My Mac (remote access, RFC 6281) and to > > > discover stolen hardware. > > >=20 > > > The issue is most pronounced on 2011 and 2012 MacBook Pros where the = IRQ > > > is shared with 3 other devices (Light Ridge Thunderbolt controller, S= DXC > > > reader, HDA card on discrete GPU). As soon as an interrupt handler is > > > installed for one of these devices, the ensuing storm of spurious IRQs > > > causes the kernel to disable the IRQ and switch to polling. This lasts > > > until the b43 driver loads and resets the device. > > >=20 > > > Loading the b43 driver first is not always an option, in particular w= ith > > > the Light Ridge Thunderbolt controller: The PCI hotplug IRQ handler g= ets > > > installed early on because it is built in, unlike b43 which is usually > > > a module. > > >=20 > > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=3D79301 > > > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=3D895951 > > > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=3D1009819 > > > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=3D1149632 =20 > >=20 > > Should also fix https://bugzilla.kernel.org/show_bug.cgi?id=3D111781 ? > > Given that this is a serious bug that can corrupt filesystems it would > > be good to see the fix in stable too. =20 >=20 > I cannot reproduce this particular issue on my MBP9,1 even though it > is architecturally very similar to your MBP10,2. I tested it with > "iommu=3Dforce intel_iommu=3Don", blacklisted b43 and stressed the machine > a bit with kernel compiles. No issues. I think you will have to stress the wireless, not the kernel. Enable iommu and let the wireless receive packets that go through the hw filters. If you have a calm network and nobody sends data to you, the card won't write anything to DMA. (This all depends on how the firmware configured the filters). --=20 Michael --Sig_/fzMTu7h3u6MhxX3sAj05oK9 Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJW/3UVAAoJEPUyvh2QjYsOY0cQALPLtCsi2xMJ5yoqV7mvgAUK mc/lmD++UoAX57+kFYvH6mgy0C+hsD6sfWw1V5RsdZ4+e2Mv/s0Pe8rY9SAk3Yip o3J4RM0QUr37d8NTvPGimVtfhvRnYKoWhjJZZ1/pduAIAZw8bg+wN7sfd8uPFfsh FsEqeCJXKQaVCIInRu1HCMDx0ttQe6pFv9+QM5glYPH4Se6sPCvIqqFz1k41+20f e743Qtm8NwVlZtp/0CI6uN5G9TGyxk574S5+NVToa9YO21scx3h01CkHSk3wdBc8 ELibvXOuRkFbkOKVjYUdFyQovOAux8rOQWPwuN+7lamamynraEJbSTbAEs61kSpG U8RqPODgdddINWz2+z2Fi+DmPD7RQmR/2o2akLWStnwZU7DlHRhZZesejZjweNfe /f1r3MZZpxPks7IUkd6Hq8qDGXICkHCLSsUg+WjNvCAGzY4dHoG+0FghdzUbXVzs /SdBm8tiyxYgeTSkE6Itc4fjb7D3tHi6FB0L3sG1FCVCPgDMT6+8mi1TMAAscdlh 7JzDobzQgZQg9dua4f517fIcfnYd6pynL6PGC9zk0Es2M3l9aLLPNlO/wp5Nfkwk r76rO03VVR9hxBeaH2Ot2ZSt/3gE1UMNkoxvd0sorW0VRUEmztiSklp5+NBVq/gg udlKOLnkgMo8AtxF/hwk =IlT2 -----END PGP SIGNATURE----- --Sig_/fzMTu7h3u6MhxX3sAj05oK9--