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The linux-next integration testing tree
86efc62d03
During initial device probe, the PCI DOE busy bit for some CXL devices may be left set for a longer period than expected by the current driver logic. Despite local comments stating DOE Busy is unlikely to be detected, it appears commonly specifically during boot when CXL devices are being probed. The symptom was messages like this: endpoint6: DOE failed -EBUSY produced by cxl_cdat_get_length() or cxl_cdat_read_table(). This was observed on a single socket AMD platform with 2 CXL memory expanders attached to the single socket. It was not the case that concurrent accesses were being made, as validated by monitoring mailbox commands on the device side. This behavior has been observed with multiple CXL memory expanders from different vendors - so it appears unrelated to the model. In all observed tests, only a small period of the retry window is actually used - typically only a handful of loop iterations. Polling on the PCI DOE Busy Bit for (at max) one PCI DOE timeout interval (1 second), resolves this issue cleanly. Per PCIe r6.2 sec 6.30.3, the DOE Busy Bit being cleared does not raise an interrupt, so polling is the best option in this scenario. Subsequent code in doe_statemachine_work() and abort paths also wait for up to 1 PCI DOE timeout interval, so this order of (potential) additional delay is presumed acceptable. Suggested-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/20241004162828.314-1-gourry@gourry.net Signed-off-by: Gregory Price <gourry@gourry.net> [bhelgaas: fix nits and add error message to commit log] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Lukas Wunner <lukas@wunner.de> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> |
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| 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 | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .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.