Dave Jiang b1956e2d07 PCI/CXL: Fail bus reset if upstream CXL Port has SBR masked
Per CXL spec r3.1, sec 8.1.5.2, the Secondary Bus Reset (SBR) bit in the
Bridge Control register of a CXL port has no effect unless the "Unmask SBR"
bit is set.

Return -ENOTTY if we attempt a bus reset on a device below a CXL Port where
"Unmask SBR" is 0.  Otherwise, the bus reset would appear to have succeeded
even though setting the bridge SBR bit had no effect.

Link: https://lore.kernel.org/linux-cxl/20240220203956.GA1502351@bhelgaas/
Link: https://lore.kernel.org/r/20240502165851.1948523-4-dave.jiang@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
[bhelgaas: simplify commit log and comments]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
2024-05-08 13:25:36 -05:00
2022-09-28 09:02:20 +02:00
2024-03-24 14:10:05 -07:00
2024-03-18 03:36:32 -06:00

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.
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