On Sat, Feb 10, 2018 at 2:05 AM, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > On Fri, Feb 09, 2018 at 02:56:43PM -0800, Alex Hung wrote: >> In recent Intel hardware the IRQs become non-configurable after BIOS >> initializes them in PEI phase and _PRS objects are no longer included in >> ASL. >> >> This is the same as "static (non-configurable) devices do not >> specify a _PRS object" in ACPI spec. As a result, error messages >> saying "ACPI Exception: AE_NOT_FOUND, Evaluating _PRS" does not need to >> be in kernel messages all the time but only when debug is enabled. > > I agree and would even go further: _PRS is optional and I don't think > there's a reason to log anything at all if it's absent. A log message > like "failed to evaluate _PRS" makes people think something is wrong > when in fact nothing is wrong. _PRS is required if the link object is pointed to by a _PRT entry. > That leads to the mindset of treating a missing _PRS as an error when > it's not. In fact, it looks like acpi_pci_link_add() *does* treat > this as an error. If _PRS doesn't exist, it skips the _CRS > evaluation. That seems wrong. I agree here. _CRS still should be evaluated if _PRS is not there in general, but in some cases the lack of _PRS *is* an error.
