00823dcbdd
Previously we assumed that all Root Ports and Switch Downstream Ports
supported Link Bandwidth Notification. Per spec, this is only required
for Ports supporting Links wider than x1 and/or multiple Link speeds
(PCIe r5.0, sec 7.5.3.6).
Because we assumed all Ports supported it, we tried to set up a Bandwidth
Notification IRQ, which failed for devices that don't support IRQs at all,
which meant pcieport didn't attach to the Port at all.
Check the Link Bandwidth Notification Capability bit and enable the service
only when the Port supports it.
[bhelgaas: commit log]
Fixes: e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification")
Link: https://lore.kernel.org/r/20210512213314.7778-1-stuart.w.hayes@gmail.com
Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org
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.