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Diffstat (limited to 'Documentation/PCI/pciebus-howto.rst')
| -rw-r--r-- | Documentation/PCI/pciebus-howto.rst | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/Documentation/PCI/pciebus-howto.rst b/Documentation/PCI/pciebus-howto.rst index f882ff62c51f..a0027e8fb0d0 100644 --- a/Documentation/PCI/pciebus-howto.rst +++ b/Documentation/PCI/pciebus-howto.rst @@ -213,8 +213,12 @@ PCI Config Registers -------------------- Each service driver runs its PCI config operations on its own -capability structure except the PCI Express capability structure, in -which Root Control register and Device Control register are shared -between PME and AER. This patch assumes that all service drivers -will be well behaved and not overwrite other service driver's -configuration settings. +capability structure except the PCI Express capability structure, +that is shared between many drivers including the service drivers. +RMW Capability accessors (pcie_capability_clear_and_set_word(), +pcie_capability_set_word(), and pcie_capability_clear_word()) protect +a selected set of PCI Express Capability Registers (Link Control +Register and Root Control Register). Any change to those registers +should be performed using RMW accessors to avoid problems due to +concurrent updates. For the up-to-date list of protected registers, +see pcie_capability_clear_and_set_word(). |