mainlining shenanigans
15d2aba7c6
The Interrupt Message Number in the PCIe Capabilities register (PCIe r4.0,
sec 7.5.3.2) indicates which MSI/MSI-X vector is shared by interrupts
related to the PCIe Capability, including Link Bandwidth Management and
Link Autonomous Bandwidth Interrupts (Link Control, 7.5.3.7), Command
Completed and Hot-Plug Interrupts (Slot Control, 7.5.3.10), and the PME
Interrupt (Root Control, 7.5.3.12).
pcie_message_numbers() checked whether we want to enable PME or Hot-Plug
interrupts but neglected to check for Link Bandwidth Management, so if we
only wanted the Bandwidth Management interrupts, it decided we didn't need
any vectors at all. Then pcie_port_enable_irq_vec() tried to reallocate
zero vectors, which failed, resulting in fallback to INTx.
On some systems, e.g., an X79-based workstation, that INTx seems broken or
not handled correctly, so we got spurious IRQ16 interrupts for Bandwidth
Management events.
Change pcie_message_numbers() so that if we want Link Bandwidth Management
interrupts, we use the shared MSI/MSI-X vector from the PCIe Capabilities
register.
Fixes:
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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 Restructured Text 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.