Return-path: Received: from cavan.codon.org.uk ([93.93.128.6]:50997 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752757AbcDEUXL (ORCPT ); Tue, 5 Apr 2016 16:23:11 -0400 Date: Tue, 5 Apr 2016 20:59:46 +0100 From: Matthew Garrett To: Bjorn Helgaas Cc: Lukas Wunner , linux-pci@vger.kernel.org, linux-wireless@vger.kernel.org, zajec5@gmail.com, b43-dev@lists.infradead.org Subject: Re: [PATCH] PCI: Add Broadcom 4331 reset quirk to prevent IRQ storm Message-ID: <20160405195946.GA18194@srcf.ucam.org> (sfid-20160405_222314_295305_CF84458B) References: <811539524df8b5ed7e2817c1c3e3e08560c97964.1459275517.git.lukas@wunner.de> <20160405194015.GC15353@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160405194015.GC15353@localhost> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, Apr 05, 2016 at 02:40:15PM -0500, Bjorn Helgaas wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=111781 and > https://mjg59.dreamwidth.org/11235.html describe a sort of similar > issue, but with DMA. An interrupt from the device is probably to > signal a DMA completion, but these problem reports only mention the > "IRQ nobody cared" issue; I don't see anything about memory > corruption. I "fixed" this with https://github.com/mjg59/grub-fedora/commit/21fcd6d79b7601e4b20ad70c5408adff2dabbc1d - doing the same in the kernel EFI stub would probably be the best way to handle it. This way you're guaranteed to stop DMA before the kernel reclaims boot services memory, which guarantees you won't have any corruption. -- Matthew Garrett | mjg59@srcf.ucam.org