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 8767827FD44; Wed, 25 Feb 2026 01:47:20 +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=1771984040; cv=none; b=IH+DVjPR49xRc/px5hAUUe5OKcE/a7EI4sP3vp1gkzRecXX3kA+wKyNyev2FtmgT21Va3OVCqAbbIFOIdURasn1wFSVdejf2m02uE+3eMGJ7HWROe/qNoM7NPYj4yYdxSuMN9M4S9OCAKZgK9kptYx3QguwCNx+N0JK4q0dnAlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771984040; c=relaxed/simple; bh=pb19MSRlqDlVeRP3yF1EP8UsmBodLoJhPrEYR+76tZU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=igcdCXuNX5HhPZnbpXMA9tX+WmvtZY4twtDTtN024nrrds2RJbnowrnqJNyR+ElJox0ZUi3c6Zp8BmnNEKQz1ynASNKHmylsQWDmIDz+Gz1/7mEj2dEm1G6ECqOvlzE7yw/0dCsNzymlGcF/MrOQG7yf4751rS6ojHLcgoygjeM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=VOJLTt/T; 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="VOJLTt/T" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4102BC116D0; Wed, 25 Feb 2026 01:47:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1771984040; bh=pb19MSRlqDlVeRP3yF1EP8UsmBodLoJhPrEYR+76tZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VOJLTt/Tj3iyAR3v3JhPTqinBmPD/Fte6E8Ajgv9+nlJ0jiRCfnB7mG33EMhx9nqS u27q3c846lfz3EC03mE3tLlEx1+SE1qFOMSbr26n1jCQa8WLNNZ3yLbkcgws0S065w myVlKTZDCMy4Zsr1jKAAIhVb29UQj8ds7ustaKJw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shuai Xue , Bjorn Helgaas , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Sasha Levin Subject: [PATCH 6.18 241/641] Documentation: tracing: Add PCI tracepoint documentation Date: Tue, 24 Feb 2026 17:19:27 -0800 Message-ID: <20260225012354.712112738@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260225012348.915798704@linuxfoundation.org> References: <20260225012348.915798704@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shuai Xue [ Upstream commit 8236fc613d44e59f6736d6c3e9efffaf26ab7f00 ] The PCI tracing system provides tracepoints to monitor critical hardware events that can impact system performance and reliability. Add documentation about it. Signed-off-by: Shuai Xue [bhelgaas: squash fixes: https://lore.kernel.org/r/20260108013956.14351-2-bagasdotme@gmail.com https://lore.kernel.org/r/20260108013956.14351-3-bagasdotme@gmail.com] Signed-off-by: Bjorn Helgaas Reviewed-by: Ilpo Järvinen Link: https://patch.msgid.link/20251210132907.58799-4-xueshuai@linux.alibaba.com Signed-off-by: Sasha Levin --- Documentation/trace/events-pci.rst | 74 ++++++++++++++++++++++++++++++ Documentation/trace/index.rst | 1 + 2 files changed, 75 insertions(+) create mode 100644 Documentation/trace/events-pci.rst diff --git a/Documentation/trace/events-pci.rst b/Documentation/trace/events-pci.rst new file mode 100644 index 0000000000000..03ff4ad30ddfa --- /dev/null +++ b/Documentation/trace/events-pci.rst @@ -0,0 +1,74 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=========================== +Subsystem Trace Points: PCI +=========================== + +Overview +======== +The PCI tracing system provides tracepoints to monitor critical hardware events +that can impact system performance and reliability. These events normally show +up here: + + /sys/kernel/tracing/events/pci + +Cf. include/trace/events/pci.h for the events definitions. + +Available Tracepoints +===================== + +pci_hp_event +------------ + +Monitors PCI hotplug events including card insertion/removal and link +state changes. +:: + + pci_hp_event "%s slot:%s, event:%s\n" + +**Event Types**: + +* ``LINK_UP`` - PCIe link established +* ``LINK_DOWN`` - PCIe link lost +* ``CARD_PRESENT`` - Card detected in slot +* ``CARD_NOT_PRESENT`` - Card removed from slot + +**Example Usage**:: + + # Enable the tracepoint + echo 1 > /sys/kernel/debug/tracing/events/pci/pci_hp_event/enable + + # Monitor events (the following output is generated when a device is hotplugged) + cat /sys/kernel/debug/tracing/trace_pipe + irq/51-pciehp-88 [001] ..... 1311.177459: pci_hp_event: 0000:00:02.0 slot:10, event:CARD_PRESENT + + irq/51-pciehp-88 [001] ..... 1311.177566: pci_hp_event: 0000:00:02.0 slot:10, event:LINK_UP + +pcie_link_event +--------------- + +Monitors PCIe link speed changes and provides detailed link status information. +:: + + pcie_link_event "%s type:%d, reason:%d, cur_bus_speed:%d, max_bus_speed:%d, width:%u, flit_mode:%u, status:%s\n" + +**Parameters**: + +* ``type`` - PCIe device type (4=Root Port, etc.) +* ``reason`` - Reason for link change: + + - ``0`` - Link retrain + - ``1`` - Bus enumeration + - ``2`` - Bandwidth notification enable + - ``3`` - Bandwidth notification IRQ + - ``4`` - Hotplug event + + +**Example Usage**:: + + # Enable the tracepoint + echo 1 > /sys/kernel/debug/tracing/events/pci/pcie_link_event/enable + + # Monitor events (the following output is generated when a device is hotplugged) + cat /sys/kernel/debug/tracing/trace_pipe + irq/51-pciehp-88 [001] ..... 381.545386: pcie_link_event: 0000:00:02.0 type:4, reason:4, cur_bus_speed:20, max_bus_speed:23, width:1, flit_mode:0, status:DLLLA diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst index b4a429dc4f7ad..0a40bfabcf19b 100644 --- a/Documentation/trace/index.rst +++ b/Documentation/trace/index.rst @@ -54,6 +54,7 @@ applications. events-power events-nmi events-msr + events-pci boottime-trace histogram histogram-design -- 2.51.0