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 C03523E49F6 for ; Thu, 15 Oct 2026 03:41:58 +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=1792035722; cv=none; b=HQFacCxniuLH35ZkKcItdmAquXltcwTQbvA/0SaR4e6NstvRNR+CYHuMwI7ntNXEwrVj9t09gRAUyyajsl4vuA7vImpv2ZRO63yvECAQolZuxTq1a87KoSrXbYw/jNT636ht3YTx4lA34ShhJWyb3u4wuCVxXMfq0gQiGGhb3Rs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792035722; c=relaxed/simple; bh=ATK3x0JN+dWnQiJE31nVuM1oU70qs1/Ikaq4Rgofm3U=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=BGkj1FxxqhT8fmy/y6faua8XLoeCf+XOAUCzKL2qsDdu1fUE34rwtwly60JsVt0NCIpozHlh733SR5/Q+LdVNFrSwgPnfJ33RDWe1EYiY/Hen0IdJclTeaQJ73Uc6QW7NBfVv109ZxgXqNTEaDE/v48f13nMv6aY/p9yyoveaPk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XcTppQfh; 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="XcTppQfh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29FD51F000C4; Thu, 15 Oct 2026 03:41:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792035718; bh=ATK3x0JN+dWnQiJE31nVuM1oU70qs1/Ikaq4Rgofm3U=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=XcTppQfhWsz+U51PbkbQe/+OnfmquHc05BkiOONXhs0GcLHzH9xEIgO9VYhePE4g5 8PolPU1rBlfNBCCQqvkHjG84sH8MGSYN3pPBCFXFH7IESnAJvsC5wbKM8dYcYvwNy1 aXkGyXfaTJ1GXFYzc8MLyhHMCCQUApTq5TLwqBn5f2VEaAPRzhG6LjXkjy0Ez6ibwa Ednt/4Ty41Zk/F2sEYlrTmV2XreSJs25HQDXg8NWu4zIrSepVaq7cZO66sEKI9FiKI 79x1XliOTe+OtH4MWrA3nzo4za2S35E13f6z4hGquz12p+N/BHFNbIRbabhMlHoPyr PGsQed0rhAn8w== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 12/18] PCI: rcar-gen4: Recover the Root Port on link down Reply-To: sashiko-reviews@lists.linux.dev To: "Koichiro Den" Cc: linux-pci@vger.kernel.org In-Reply-To: <20261015033103.3076869-13-den@valinux.co.jp> References: <20261015033103.3076869-1-den@valinux.co.jp> <20261015033103.3076869-13-den@valinux.co.jp> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 15 Oct 2026 03:41:57 +0000 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > On R-Car, the controller's reset requests (smlh_req_rst_not, > link_req_rst_not) arrive on intreq_pcim_sub, the interrupt the MSIs are > demultiplexed from, so DBI is read as soon as the link goes down. On > R-Car S4 that is a hazard: DBI accesses issued within a few hundred > microseconds of an unexpected link down do not complete and hang the > host. In testing, the first Root Port config read after powering off > the link partner hung unless delayed by ~300 us. >=20 > Check the APP reset status in the interrupt handler before DBI is > touched. When a reset request is latched, flag the controller as > needing reinitialization, which masks the sources, ack the request and > schedule recovery work. The work calls pci_host_handle_link_down() on > the Root Port, which runs the AER-style recovery and resets the > controller through reset_root_port(), holding a reference on the port. > If the Root Port is absent when the work runs, reset the controller > [ ... ] > recovery can run once the system thaws. Disarm Root Port events during > suspend and re-arm them in .post_init() after resume has set up the > link, so taking the link down for suspend does not start recovery. >=20 > Signed-off-by: Koichiro Den Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261015033103.3076= 869-1-den@valinux.co.jp?part=3D12