On Fri, Aug 02, 2024 at 08:24:49AM -0600, Keith Busch wrote: > Which itself follows the existing pattern from > pci_create_resource_files(), which creates a write combine > resource<X>_wc file only when IORESOURCE_PREFETCH is set. But yeah, > prefetch isn't necessary for wc, but it seems to indicate it's safe. Apparently IORESOURCE_PREFETCH never implied anything about write combinability, and Linux got this wrong long time ago. The fact that we do this now clashes with PCI SIGs desire to kill the concept of prefetcable BARs that they are forcing down everyones throat.
