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 26A603B6370 for ; Thu, 20 Aug 2026 06:52:31 +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=1787208753; cv=none; b=atS5Oub2vzKwbCFxVoYLGyxnYtqecrFo3Pce7bmfPt9O/uVG2/4BGC+G7k2pXasQ+TE1WH2KqXsDruFMreS7RGCNW8JvHSugirlUSYeuU/RYH5wfVFI/h5e72CI1qvSzceEUBHVbX1IhhYXjNNQU0Jtv3jotRgJXRe1dJBiY+n4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787208753; c=relaxed/simple; bh=jc7dxDCyUvOGX9J9Rq7iRNQprzCbX+Q2LfMFqUm2uic=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=ihcYxp7MFJgWv/uM5QI1rj4Ep5S1jUzBrGbM4PTH990FqnH9lMEzqrsqjyHaQOodBWpHUSedTp6UN3quEIFn/elpT9c5DSIYieg6H4D/x48MfHc1Tek/Bo4aKHLaFLHHAOZBPsg2JdAr7kS7VGlhA4VdVR3H9XwJhQTpHl6geQ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KViKMYBa; 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="KViKMYBa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B07911F000E9; Thu, 20 Aug 2026 06:52:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787208751; bh=jc7dxDCyUvOGX9J9Rq7iRNQprzCbX+Q2LfMFqUm2uic=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=KViKMYBaGLFNt1ZmGXTP2xL2fd/I/7h1Onh48W/xaD7ZWSX7jw5frM1UNClmXzHc7 he4f9B2Tg89J6PxBQFIx2Pr2C+TYefZpIu0PrXO4uvExRS4vd/ozv9nMdmsW4eoH44 SsQgNHky7sI0rWSFHoQAGHGlM9zNn5O4PgV8ZtFUhlN0bUi3+JXpiaYG07U7GL67Zf Odp+AsJRk3RPQNAs/D2hk6n5C/QiuRr45ExYqMOi0VVyfuwHmX0U+/ADs33NDaXtDN dndCzMnXPrYMe46cP2WdF7n1Q3f/Aqc6NwJJPFuT3E7nvr/r3EfwsyhYtnw4Xbophk fSoMt+MsBlE5Q== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2] PCI: qcom: Block accesses to downstream devices on link down Reply-To: sashiko-reviews@lists.linux.dev To: "Qiang Yu" Cc: linux-pci@vger.kernel.org In-Reply-To: <20260819-ecam_blocker-v2-1-e7a8fdc1c5cb@oss.qualcomm.com> References: <20260819-ecam_blocker-v2-1-e7a8fdc1c5cb@oss.qualcomm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 20 Aug 2026 06:52:31 +0000 Message-Id: <20260820065231.B07911F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > After a PCIe link goes down, software may still access the BAR (MMIO) > space or configuration space of devices behind that link before recovery > has run. As the link is down, these accesses never complete, resulting in > a storm of Completion Timeout AERs. >=20 > Use the controller's ECAM blocker to drop these accesses to the PCIe > address space as soon as the link-down interrupt fires, so that Completion > Timeout AERs are reduced. The blocked range covers the entire address > space (base 0x0, all-ones limit), since the Root Port's own DBI/iATU > register space remains accessible regardless. >=20 > The range is programmed once in the host init path, since the range > registers are wiped by BCR reset. This leaves only the ECAM_BLOCKER_EN > bit to be flipped from the link-down IRQ handler, so the blocker can be > armed with a single fast register write for immediate effect. > [ ... ] > with a Root Port reset triggered independently through AER, which > reprograms PARF_SYS_CTRL as part of reinitializing the controller. > Serialize these with a per-controller mutex. >=20 > Signed-off-by: Qiang Yu Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260819-ecam_block= er-v2-1-e7a8fdc1c5cb@oss.qualcomm.com?part=3D1