mirror of
https://github.com/torvalds/linux.git
synced 2026-08-02 13:22:02 +02:00
Linux kernel source tree
044b9f1a7f
We have a Switch Upstream Port (2b:00.0) that has a PTM Capability, but
doesn't advertise support for any PTM roles:
Capabilities: [220 v1] Precision Time Measurement
PTMCap: Requester- Responder- Root-
Linux enables PTM without looking into what roles it actually supports, and
apparently the Port immediately sends PTM Requests even though it doesn't
support the PTM Requester role. The messages include an invalid bus number,
so the Root Port detects an ACS Violation (see the PCIe r7.0, sec 6.12.1.1,
implementation note):
pci 0000:2b:00.0: [8086:5786] type 01 class 0x060400 PCIe Switch Upstream Port
pci 0000:2b:00.0: PTM enabled, 4ns granularity
pcieport 0000:00:07.1: AER: Multiple Uncorrectable (Non-Fatal) error message received from 0000:00:07.1
pcieport 0000:00:07.1: PCIe Bus Error: severity=Uncorrectable (Non-Fatal), type=Transaction Layer, (Receiver ID)
pcieport 0000:00:07.1: device [8086:e44f] error status/mask=00200000/00000000
pcieport 0000:00:07.1: [21] ACSViol (First)
pcieport 0000:00:07.1: AER: TLP Header: 0x34000000 0x00000052 0x00000000 0x00000000
The TLP Header shows a 4 DW header, no data (001b) Msg with Local routing
(1 0100b) with Requester ID 0x0000 and PTM Request code (0x52).
Fix this by enabling PTM only if the following conditions are true (see sec
6.21.1 figure 6-21):
- Endpoint must advertise PTM Requester Capable
- Switch Upstream Port must advertise PTM Responder Capable
- Root Port must advertise PTM Root Capable
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
[bhelgaas: commit log, comments]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20251112074614.1440266-1-mika.westerberg@linux.intel.com
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.