From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2A3182F9992; Tue, 26 Aug 2025 13:45:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756215935; cv=none; b=hn/l09zGx677WyjY1SAgV0khahwtqTsOs2HIEb+OvnOLFhHD30kobnU27lvgys7uAqJ1KPkqeCJICSrXY1t9SciMmAIjBnjfxPdcxJqSNA7/nq670pRtxh4JspHXI5Lp+y4JOZ9V5lQSbkrwonX+HT/tF9Td60YU0uEGwCgVHUQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756215935; c=relaxed/simple; bh=sIT1oanR6vpJDTqXjlrkNZmfZ/aOBL5hGRmlClVzBR0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=l4rvi0ZIOkP8FmAO+omKFCZ8u++iIGq9sNhl6DvycfIzgV5wLVG0GNSJzsuUHaUbKxhijsxBp+EnbvdkBEHImSPKoc7eunkBIjDdJQzDPoCdiJqUWssIdC7a2b+uvo/I5/A2PLmz4PLdhRwXCQBMlXmMcLCOjmaeB13N0U/hVI0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=svHa/a+H; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="svHa/a+H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE225C4CEF1; Tue, 26 Aug 2025 13:45:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756215935; bh=sIT1oanR6vpJDTqXjlrkNZmfZ/aOBL5hGRmlClVzBR0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=svHa/a+HqfJo1i33KjJfqIEXRQGHwK8qUQW5q1k0vEA+Jwyu4Vdm5aHYdljq2Ueij 36Z8myUWxQ2T0o0OT8K4Lvi1efmCiNAaPjOIrofngqM6kiL8ZAWvMSqcaVtcsOSuvS PmH5Wl1adWNSYA63e1LTuVBgPdVrlNPj/yJdmU6U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shawn Anastasio , Timothy Pearson , Bjorn Helgaas , Madhavan Srinivasan , Sasha Levin Subject: [PATCH 5.15 221/644] PCI: pnv_php: Work around switches with broken presence detection Date: Tue, 26 Aug 2025 13:05:12 +0200 Message-ID: <20250826110951.902973444@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110946.507083938@linuxfoundation.org> References: <20250826110946.507083938@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Timothy Pearson [ Upstream commit 80f9fc2362797538ebd4fd70a1dfa838cc2c2cdb ] The Microsemi Switchtec PM8533 PFX 48xG3 [11f8:8533] PCIe switch system was observed to incorrectly assert the Presence Detect Set bit in its capabilities when tested on a Raptor Computing Systems Blackbird system, resulting in the hot insert path never attempting a rescan of the bus and any downstream devices not being re-detected. Work around this by additionally checking whether the PCIe data link is active or not when performing presence detection on downstream switches' ports, similar to the pciehp_hpc.c driver. Signed-off-by: Shawn Anastasio Signed-off-by: Timothy Pearson Signed-off-by: Bjorn Helgaas Signed-off-by: Madhavan Srinivasan Link: https://patch.msgid.link/505981576.1359853.1752615415117.JavaMail.zimbra@raptorengineeringinc.com Signed-off-by: Sasha Levin --- drivers/pci/hotplug/pnv_php.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/pci/hotplug/pnv_php.c b/drivers/pci/hotplug/pnv_php.c index c1c1d30bd86b..f99987f26ff0 100644 --- a/drivers/pci/hotplug/pnv_php.c +++ b/drivers/pci/hotplug/pnv_php.c @@ -389,6 +389,20 @@ static int pnv_php_get_power_state(struct hotplug_slot *slot, u8 *state) return 0; } +static int pcie_check_link_active(struct pci_dev *pdev) +{ + u16 lnk_status; + int ret; + + ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status); + if (ret == PCIBIOS_DEVICE_NOT_FOUND || PCI_POSSIBLE_ERROR(lnk_status)) + return -ENODEV; + + ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA); + + return ret; +} + static int pnv_php_get_adapter_state(struct hotplug_slot *slot, u8 *state) { struct pnv_php_slot *php_slot = to_pnv_php_slot(slot); @@ -401,6 +415,19 @@ static int pnv_php_get_adapter_state(struct hotplug_slot *slot, u8 *state) */ ret = pnv_pci_get_presence_state(php_slot->id, &presence); if (ret >= 0) { + if (pci_pcie_type(php_slot->pdev) == PCI_EXP_TYPE_DOWNSTREAM && + presence == OPAL_PCI_SLOT_EMPTY) { + /* + * Similar to pciehp_hpc, check whether the Link Active + * bit is set to account for broken downstream bridges + * that don't properly assert Presence Detect State, as + * was observed on the Microsemi Switchtec PM8533 PFX + * [11f8:8533]. + */ + if (pcie_check_link_active(php_slot->pdev) > 0) + presence = OPAL_PCI_SLOT_PRESENT; + } + *state = presence; ret = 0; } else { -- 2.39.5