[PATCH] PCI: Add Broadcom 4331 reset quirk to prevent IRQ storm

Sun Apr 3 04:49:12 PDT 2016

Hi Andrew,

On Sat, Apr 02, 2016 at 10:40:41PM +1100, Andrew Worsley wrote:
> On 30 March 2016 at 04:41, Lukas Wunner <lukas at wunner.de> wrote:
> > Broadcom 4331 wireless cards built into Apple Macs unleash an IRQ storm
> > 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 Cupertino.
> > 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.
> >
> > The issue is most pronounced on 2011 and 2012 MacBook Pros where the IRQ
> > is shared with 3 other devices (Light Ridge Thunderbolt controller, SDXC
> > 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.
> >
> > Loading the b43 driver first is not always an option, in particular with
> > the Light Ridge Thunderbolt controller: The PCI hotplug IRQ handler gets
> > installed early on because it is built in, unlike b43 which is usually
> > a module.
> >
> > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=79301
> > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=895951
> > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1009819
> > Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1149632
> 
> I do see an irq 17 problem on my macbook, but I thought grub is
> supposed to stop the boardcom wireless?
> 
> Investigating grub2 git://git.savannah.gnu.org/grub.git I see this
> patch  rev 9d34bb8 which says it disables Broadcom wireless hardware
> on Apples:

Thanks for the pointer to the grub2 commit, I wasn't aware of that.

The commit puts the wireless card in power state D3hot but that doesn't
stop it from sending interrupts. I have just tested that. So it's
perfectly plausible that you're still seeing spurious interrupts
despite using grub. Please test the patch I've posted, the spurious
interrupts should disappear. If you "cat /proc/interrupts", you should
then only see a few hundred interrupts on IRQ 17. Without the patch it
should be in the 100000+ range.

Best regards,

Lukas

> 
> * commit 9d34bb8
> | Author: Matthew Garrett <mjg at redhat.com>
> | Date:   Thu May 3 17:26:55 2012 +0200
> |
> |       Suspend broadcom cards in order to stop their DMA.
> |
> |       * grub-core/Makefile.am (KERNEL_HEADER_FILES): Add pci.h on x86 EFI.
> |       * grub-core/Makefile.core.def (kernel): Add pci.c on x86 EFI.
> |       (pci): Don't build on x86 EFI.
> |       * grub-core/bus/pci.c (grub_pci_find_capability): New function.
> |       * grub-core/kern/efi/mm.c (stop_broadcom) [__i386__ || __x86_64__]:
> |       New function.
> |       (grub_efi_finish_boot_services) [__i386__ || __x86_64__]: Call
> |       stop_broadcom if running on EFI.
> |       * include/grub/pci.h (GRUB_PCI_CLASS_NETWORK): New enum value.
> |       (GRUB_PCI_CAP_POWER_MANAGEMENT): Likewise.
> |       (GRUB_PCI_VENDOR_BROADCOM): Likewise.
> |       (grub_pci_find_capability): New proto.
> |
> |       Also-By: Vladimir Serbinenko <phcoder at gmail.com>
> |
> | M     ChangeLog
> | M     grub-core/Makefile.am
> | M     grub-core/Makefile.core.def
> | M     grub-core/bus/pci.c
> | M     grub-core/kern/efi/mm.c
> | M     include/grub/pci.h
> 
> But I run debian grub2-common 2.02~beta2-22+deb8u1 which has this fix
> and I *still* get this irq issue
> 
> ....
> [  608.242849] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called
> with disabled ep ffff88008a19df48
> [  608.242851] xhci_hcd 0000:00:14.0: xHCI xhci_drop_endpoint called
> with disabled ep ffff88008a19df90
> [  608.254975] irq 17: nobody cared (try booting with the "irqpoll" option)
> [  608.254979] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G         C O
> 3.16.0-4-amd64 #1 Debian 3.16.7-ckt20-1+deb8u4
> [  608.254981] Hardware name: Apple Inc.
> MacBookPro10,1/Mac-C3EC7CD22292981F, BIOS
> MBP101.88Z.00EE.B00.1205101839 05/10/2012
> [  608.254985]  ffff88045a85bac4 ffffffff8150dcff ffff88045a85ba00
> ffffffff810bd3ad
> [  608.254987]  ffff88045a85ba00 0000000000000011 0000000000000000
> ffffffff810bd8d1
> [  608.254989]  0000000000000000 0000000000000000 0000000000000011
> 0000000000000000
> [  608.254990] Call Trace:
> [  608.254999]  <IRQ>  [<ffffffff8150dcff>] ? dump_stack+0x41/0x51
> [  608.255006]  [<ffffffff810bd3ad>] ? __report_bad_irq+0x2d/0xc0
> [  608.255010]  [<ffffffff810bd8d1>] ? note_interrupt+0x241/0x290
> [  608.255013]  [<ffffffff810bb0f1>] ? handle_irq_event_percpu+0xa1/0x190
> [  608.255017]  [<ffffffff810bb218>] ? handle_irq_event+0x38/0x60
> [  608.255020]  [<ffffffff810be413>] ? handle_fasteoi_irq+0x83/0x150
> [  608.255025]  [<ffffffff810150cd>] ? handle_irq+0x1d/0x30
> [  608.255029]  [<ffffffff81516cd9>] ? do_IRQ+0x49/0xe0
> [  608.255033]  [<ffffffff81514b2d>] ? common_interrupt+0x6d/0x6d
> [  608.255037]  <EOI>  [<ffffffff8108aded>] ?
> __hrtimer_start_range_ns+0x1cd/0x390
> [  608.255041]  [<ffffffff813dfd42>] ? cpuidle_enter_state+0x52/0xc0
> [  608.255044]  [<ffffffff813dfd38>] ? cpuidle_enter_state+0x48/0xc0
> [  608.255047]  [<ffffffff810a80d8>] ? cpu_startup_entry+0x2f8/0x400
> [  608.255051]  [<ffffffff81903076>] ? start_kernel+0x497/0x4a2
> [  608.255054]  [<ffffffff81902a04>] ? set_init_arg+0x4e/0x4e
> [  608.255057]  [<ffffffff81902120>] ? early_idt_handler_array+0x120/0x120
> [  608.255060]  [<ffffffff8190271f>] ? x86_64_start_kernel+0x14d/0x15c
> [  608.255061] handlers:
> [  608.255088] [<ffffffffa0645730>] azx_interrupt [snd_hda_controller]
> [  608.255089] Disabling IRQ #17
> [  608.354706] usb 1-2: reset high-speed USB device number 3 using xhci_hcd
> ...