Changes since v4[1]: - Collect an ack for patch 1 (Rafael) - Fix commit subject wording in patch 2 (Rafael) - Fix a debug print in patch 2 (Rafael) - Document the reasoning behind calculation of cxl hotplug support (David) - A few definition and variable name changes to make the new _OSC DWORDS generic instead of CXL specific (Rafael) Add support for using the CXL definition of _OSC where applicable, and negotiating CXL specific support and control bits. Patch 1 is a preliminary cleanup that replaces open-coded pointer arithmetic to retrieve the Control DWORD with an inline helper. Patch 2 adds the new CXL _OSC UUID, and uses it instead of the PCI UUID when a root port is CXL enabled. It provides a fallback method for CXL-1.1 platforms that may not implement the CXL-2.0 _OSC. Patch 3 performs negotiation for the CXL specific _OSC support and control bits. I've tested these against a custom qemu[2], which adds the CXL _OSC (in addition to other CXL support). Specifically, _OSC support is added here[3]. [1]: https://lore.kernel.org/linux-cxl/20220331202022.1823174-1-vishal.l.verma@xxxxxxxxx [2]: https://gitlab.com/jic23/qemu/-/tree/cxl-v8-draft [3]: https://gitlab.com/jic23/qemu/-/commit/1d67df6b6e3716c27462873f3451956f5c0673a3 Dan Williams (1): PCI/ACPI: Prefer CXL _OSC instead of PCIe _OSC for CXL host bridges Vishal Verma (2): PCI/ACPI: add a helper for retrieving _OSC Control DWORDs PCI/ACPI: negotiate CXL _OSC include/linux/acpi.h | 42 ++++++- include/acpi/acpi_bus.h | 12 +- drivers/acpi/bus.c | 2 +- drivers/acpi/pci_root.c | 240 +++++++++++++++++++++++++++++++++++----- 4 files changed, 262 insertions(+), 34 deletions(-) base-commit: 05e815539f3f161585c13a9ab023341bade2c52f -- 2.35.1
