From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.173 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792518593; b=sbeklegJrOEsUL6tbpCM1QotPQmYzx4xlmb7Lkfx4bbhcarvo7Oy13Yo3iqVy7rY5BBE xaJuG/TVrBYkVaJpGgemHx7Ed3BK+NSaYfKHGBf1/uPHoJlc/Dk6acVeDIH0xAFEcqw3i KJUEfWo6Nmu4tMh9R1JHhWaED4NwNa0zWWq5Ic0eEteGNNAsHC2jFUZzWyL+WPzfUJJjv WQg1UPMYgq+Q/p72wF1v+nG7sAl6wiIXEJBsRmZ2VmJ2uVS7F4PMycCGT8Sk/O8PUjtiV YsG/zg7OK99liL1eo8g2BZfcb7LHu99rUCOIkMZwkNzd0aSdG620phEB9y5iIqDkb0w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792518593; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Content-Type:Content-Transfer-Encoding: From:Mime-Version:Subject:Date:Message-Id:References:Cc:In-Reply-To: To:X-Mailer; bh=VdO3TkGJkE0/5auvzRmeM+H+7fXA7G0lgo2mz/y/Xz4=; b=VRPqoWYuFjj5FR3PZRUR95UL5xMD+ZRUuEq177tJtfQrWt5cD0Bl4OHdObl9DQzhSFst S3uGOk87N7Q7/34E4hPTnTr8a7OoT866cn8aUMplG/kwEAa6V0u8yBdDQffv9GPTCIhQg sjgJSui4/O9Jw+BoSSA+98kI2wIXhgF7ZZN0kJ7J3jw/5d4OBMNSEJ6d8DW8ObTLqNY/O aqVFauyOqXZ94WktOVf67U32QMZX0UV6Q77UR5vh7y5l3IOAjwtBRukIIQVTbB7Z+1XcA 2a4dMkdlDZvSS5OZwwzK0CIrDdV2FPPM2ANjdwT0Q7iz4KsTV5N8bp4+FKuHTprsHvQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; arc=none smtp.remote-ip=95.215.58.173 Received: from mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C6235606A31B for ; Tue, 20 Oct 2026 17:49:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org C6235606A31B Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=VdO3TkGJkE0/5auvzRmeM+H+7fXA7G0lgo2mz/y/Xz4=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792518585; v=1; x=1793123385; b=RBtdtnz8TwYDn2UOv5vbA6DVvZ9hjToKOK3loqZfafR1McdaLsW9UNaNv/XB0d7HQVMpJgnH v7Jvx2P6yxicTdn9rKuXvfbtNgIRUpdHBilxA8vU69knmzfU49j5gGJ1H4gHP6nyF1My+57FeeC SzJUNRGnzxKwsWD/COZ61Omg= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta10.migadu.com with ESMTPS id 27681babf8702918; Tue, 20 Oct 2026 17:49:44 +0000 X-Mizu-Trace-ID: 27681babf8702918 X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Aditya Garg X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 (1.0) Subject: Re: [REGRESSION] intel-iommu/brcmfmac DMAR fault on Broadcom PCIe wifi, v7.3-rc7 -> v7.3 final -- candidate mechanism and proposed fix path Date: Tue, 20 Oct 2026 23:19:29 +0530 Message-Id: References: <1a15a4b49f0.2873.9b12b7fc0a3841636cfb5e919b41b954@broadcom.com> Cc: Jason Perlow , baolu.lu@linux.intel.com, dwmw2@infradead.org, iommu@lists.linux.dev, bhelgaas@google.com, linux-pci@vger.kernel.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, regressions@lists.linux.dev, regressions@leemhuis.info In-Reply-To: <1a15a4b49f0.2873.9b12b7fc0a3841636cfb5e919b41b954@broadcom.com> To: Arend van Spriel X-Mailer: iPad Mail (24A446) > On 20 Oct 2026, at 10:40=E2=80=AFPM, Arend van Spriel wrote: >=20 > =EF=BB=BFOp 20 oktober 2026 18:02:30 schreef Jason Perlow : >=20 >> NOTE: an earlier report on this bug from us bounced off one of these list= s due to HTML/multipart formatting from the mail client used -- apologies, s= witching clients. This mail includes the full original report plus a follow-= up, merged into one self-contained report since the original never reached a= nyone. >>=20 >> =3D=3D=3D ORIGINAL REPORT =3D=3D=3D >>=20 >> Hardware: Intel CoffeeLake-H platforms, various. The affected device is a= Broadcom BCM4364 802.11ac PCIe wifi adapter (14e4:4464) at 0000:05:00.0 on a= n Apple MacBookPro16,1 (T2 Mac). Aditya, including you directly since this i= s T2 hardware; copying iommu/pci/wireless because the fault signature and th= e fact that it reproduces on only one of five tested machines (at the time o= f the original report -- see follow-up below, that has since changed) looked= like it needed eyes on the core IOMMU/PCI path, not the driver. >=20 > [...] >=20 >> THE ONE ANOMALY WE CAN'T YET EXPLAIN >>=20 >> Despite the last two items above being unchanged, the actual generated .c= onfig has CONFIG_INTEL_IOMMU_DEFAULT_ON unset after make olddefconfig agains= t the rc7 source tree, but =3Dy after the same process against the final sou= rce tree, even though our template explicitly answers "# CONFIG_INTEL_IOMMU_= DEFAULT_ON is not set" in both cases. Our working theory is that some other s= ymbol started selecting/implying INTEL_IOMMU_DEFAULT_ON between rc7 and fina= l -- which would override an explicitly-seeded "not set" answer during oldde= fconfig resolution -- but we have not identified which one yet. intel_iommu=3Doff has the same effect as disabling this in the kernel config= . The real question is WiFi was still working before when intel_iommu was on= . I wonder if PCs with Broadcom chips are also getting affected since we have a= confirmed report of a non T2 Mac as well.