On 10.09.2019 11:46, Igor Druzhinin wrote: > On 10/09/2019 02:47, Boris Ostrovsky wrote: >> On 9/9/19 5:48 PM, Igor Druzhinin wrote: >>> Actually, pci_mmcfg_late_init() that's called out of acpi_init() - >>> that's where MCFG areas are properly sized. >> >> pci_mmcfg_late_init() reads the (static) MCFG, which doesn't need DSDT >> parsing, does it? setup_mcfg_map() OTOH does need it as it uses data from >> _CBA (or is it _CRS?), and I think that's why we can't parse MCFG prior to >> acpi_init(). So what I said above indeed won't work. >> > > No, it uses is_acpi_reserved() (it's called indirectly so might be well > hidden) to parse DSDT to find a reserved resource in it and size MCFG > area accordingly. setup_mcfg_map() is called for every root bus > discovered and indeed tries to evaluate _CBA but at this point > pci_mmcfg_late_init() has already finished MCFG registration for every > cold-plugged bus (which information is described in MCFG table) so those > calls are dummy.
I don't think they're strictly dummy. Even for boot time available devices iirc there's no strict requirement for there to be respective data in MCFG. Such a requirement exists only for devices which are actually needed to start the OS (disk or network, perhaps video or alike), or maybe even just its loader. Jan
