From: Lukas Wunner Date: Mon, 23 Mar 2026 06:52:39 +0000 (+0100) Subject: Documentation: PCI: Document PCIe TLP Header decoder for AER messages X-Git-Tag: v7.0-rc6~29^2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=05f643d6f7e699198ccc47e634de3879a8ec26a3;p=thirdparty%2Flinux.git Documentation: PCI: Document PCIe TLP Header decoder for AER messages The prefix/header of a TLP that caused an error may be recorded in the AER Capability and emitted to the kernel log in raw hex format. Document the existence and usage of tlp-tool, which decodes the TLP Header into human-readable form. The TLP Header hints at the root cause of an error, yet is often ignored because of its seeming opaqueness. Instead, PCIe errors are frequently worked around by a change in the kernel without fully understanding the actual source of the problem. With more documentation on available tools we'll hopefully come up with better solutions. There are also wireshark dissectors for TLPs, but it seems they expect a complete TLP, not just the header, and they cannot grok the hex format emitted by the kernel directly. tlp-tool appears to be the most cut and dried solution out there. Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Mika Westerberg Cc: Maciej Grochowski Link: https://patch.msgid.link/bf826c41b4c1d255c7dcb16e266b52f774d944ed.1774246067.git.lukas@wunner.de --- diff --git a/Documentation/PCI/pcieaer-howto.rst b/Documentation/PCI/pcieaer-howto.rst index 3210c4792978..90fdfddd3ae5 100644 --- a/Documentation/PCI/pcieaer-howto.rst +++ b/Documentation/PCI/pcieaer-howto.rst @@ -85,6 +85,16 @@ In the example, 'Requester ID' means the ID of the device that sent the error message to the Root Port. Please refer to PCIe specs for other fields. +The 'TLP Header' is the prefix/header of the TLP that caused the error +in raw hex format. To decode the TLP Header into human-readable form +one may use tlp-tool: + +https://github.com/mmpg-x86/tlp-tool + +Example usage:: + + curl -L https://git.kernel.org/linus/2ca1c94ce0b6 | rtlp-tool --aer + AER Ratelimits --------------