mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 13:13:57 +08:00
60f75b8e97
In theory, under a given ACPI namespace node there should be only one child device object with _ADR whose value matches a given bus address exactly. In practice, however, there are systems in which multiple child device objects under a given parent have _ADR matching exactly the same address. In those cases we use _STA to determine which of the multiple matching devices is enabled, since some systems are known to indicate which ACPI device object to associate with the given physical (usually PCI) device this way. Unfortunately, as it turns out, there are systems in which many device objects under the same parent have _ADR matching exactly the same bus address and none of them has _STA, in which case they all should be regarded as enabled according to the spec. Still, if those device objects are supposed to represent bridges (e.g. this is the case for device objects corresponding to PCIe ports), we can try harder and skip the ones that have no child device objects in the ACPI namespace. With luck, we can avoid using device objects that we are not expected to use this way. Although this only works for bridges whose children also have ACPI namespace representation, it is sufficient to address graphics adapter detection issues on some systems, so rework the code finding a matching device ACPI handle for a given bus address to implement this idea. Introduce a new function, acpi_find_child(), taking three arguments: the ACPI handle of the device's parent, a bus address suitable for the device's bus type and a bool indicating if the device is a bridge and make it work as outlined above. Reimplement the function currently used for this purpose, acpi_get_child(), as a call to acpi_find_child() with the last argument set to 'false' and make the PCI subsystem use acpi_find_child() with the bridge information passed as the last argument to it. [Lan Tianyu notices that it is not sufficient to use pci_is_bridge() for that, because the device's subordinate pointer hasn't been set yet at this point, so use hdr_type instead.] This change fixes a regression introduced inadvertently by commit |
||
|---|---|---|
| .. | ||
| platform | ||
| acbuffer.h | ||
| acconfig.h | ||
| acexcep.h | ||
| acnames.h | ||
| acoutput.h | ||
| acpi_bus.h | ||
| acpi_drivers.h | ||
| acpi_numa.h | ||
| acpi.h | ||
| acpiosxf.h | ||
| acpixf.h | ||
| acrestyp.h | ||
| actbl1.h | ||
| actbl2.h | ||
| actbl3.h | ||
| actbl.h | ||
| actypes.h | ||
| apei.h | ||
| button.h | ||
| ghes.h | ||
| hed.h | ||
| pdc_intel.h | ||
| processor.h | ||
| reboot.h | ||
| video.h | ||