From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) (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 216503FCC for ; Tue, 24 Aug 2021 16:07:33 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10086"; a="217375370" X-IronPort-AV: E=Sophos;i="5.84,347,1620716400"; d="scan'208";a="217375370" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 09:07:29 -0700 X-IronPort-AV: E=Sophos;i="5.84,347,1620716400"; d="scan'208";a="575064522" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.25]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 09:07:28 -0700 Subject: [PATCH v3 23/28] cxl/acpi: Do not add DSDT disabled ACPI0016 host bridge ports From: Dan Williams To: linux-cxl@vger.kernel.org Cc: Alison Schofield , stable@vger.kernel.org, vishal.l.verma@intel.com, nvdimm@lists.linux.dev, Jonathan.Cameron@huawei.com, ira.weiny@intel.com, ben.widawsky@intel.com, vishal.l.verma@intel.com, alison.schofield@intel.com Date: Tue, 24 Aug 2021 09:07:28 -0700 Message-ID: <162982124835.1124374.16212896894542743429.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <162982112370.1124374.2020303588105269226.stgit@dwillia2-desk3.amr.corp.intel.com> References: <162982112370.1124374.2020303588105269226.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit From: Alison Schofield During CXL ACPI probe, host bridge ports are discovered by scanning the ACPI0017 root port for ACPI0016 host bridge devices. The scan matches on the hardware id of "ACPI0016". An issue occurs when an ACPI0016 device is defined in the DSDT yet disabled on the platform. Attempts by the cxl_acpi driver to add host bridge ports using a disabled device fails, and the entire cxl_acpi probe fails. The DSDT table includes an _STA method that sets the status and the ACPI subsystem has checks available to examine it. One such check is in the acpi_pci_find_root() path. Move the call to acpi_pci_find_root() to the matching function to prevent this issue when adding either upstream or downstream ports. Suggested-by: Dan Williams Signed-off-by: Alison Schofield Fixes: 7d4b5ca2e2cb ("cxl/acpi: Add downstream port data to cxl_port instances") Cc: Signed-off-by: Dan Williams --- drivers/cxl/acpi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c index 8ae89273f58e..2d8f1ec1abff 100644 --- a/drivers/cxl/acpi.c +++ b/drivers/cxl/acpi.c @@ -243,6 +243,9 @@ static struct acpi_device *to_cxl_host_bridge(struct device *dev) { struct acpi_device *adev = to_acpi_device(dev); + if (!acpi_pci_find_root(adev->handle)) + return NULL; + if (strcmp(acpi_device_hid(adev), "ACPI0016") == 0) return adev; return NULL; @@ -266,10 +269,6 @@ static int add_host_bridge_uport(struct device *match, void *arg) if (!bridge) return 0; - pci_root = acpi_pci_find_root(bridge->handle); - if (!pci_root) - return -ENXIO; - dport = find_dport_by_dev(root_port, match); if (!dport) { dev_dbg(host, "host bridge expected and not found\n"); @@ -282,6 +281,7 @@ static int add_host_bridge_uport(struct device *match, void *arg) return PTR_ERR(port); dev_dbg(host, "%s: add: %s\n", dev_name(match), dev_name(&port->dev)); + pci_root = acpi_pci_find_root(bridge->handle); ctx = (struct cxl_walk_context){ .dev = host, .root = pci_root->bus,