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The driver triggers a "Secondary Bus Reset" (SBR) by calling __pci_reset_function_locked() which asserts the SBR bit in the "Bridge Control Register" in the configuration space of the upstream bridge for 2ms. This is done without locking the configuration space of the upstream bridge port, allowing user space to access it concurrently. Linux 6.11 will start warning about such unlocked resets [1][2]: pcieport 0000:00:01.0: unlocked secondary bus reset via: pci_reset_bus_function+0x51c/0x6a0 Avoid the warning and the concurrent access by locking the configuration space of the upstream bridge prior to the reset and unlocking it afterwards. [1] https://lore.kernel.org/all/171711746953.1628941.4692125082286867825.stgit@dwillia2-xfh.jf.intel.com/ [2] https://lore.kernel.org/all/20240531213150.GA610983@bhelgaas/ Signed-off-by: Ido Schimmel <idosch@nvidia.com> Signed-off-by: Petr Machata <petrm@nvidia.com> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com> Link: https://patch.msgid.link/9937b0afdb50f2f2825945393c94c093c04a5897.1720447210.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski <kuba@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 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.