On 10 November 2016 at 06:49, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > On Wed, Nov 09, 2016 at 08:29:23PM +0000, Ard Biesheuvel wrote: >> Hi Bjorn, >> >> On 9 November 2016 at 20:06, Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: >> > On Wed, Nov 09, 2016 at 02:25:56PM -0500, Christopher Covington wrote: >> >> Hi Bjorn, >> >> >> [...] >> >> >> >> We're working to add the PNP0C02 resource to future firmware, but it's >> >> not in the current firmware. Are dmesg and /proc/iomem from the >> >> current firmware interesting or should we wait for the update to file? >> > >> > Note that the ECAM space is not the only thing that should be >> > described via these PNP0C02 devices. *All* non-enumerable resources >> > should be described by the _CRS method of some ACPI device. Here's a >> > sample from my laptop: >> > >> > PCI: MMCONFIG for domain 0000 [bus 00-3f] at [mem 0xf8000000-0xfbffffff] (base 0xf8000000) >> > system 00:01: [io 0x1800-0x189f] could not be reserved >> > system 00:01: [io 0x0800-0x087f] has been reserved >> > system 00:01: [io 0x0880-0x08ff] has been reserved >> > system 00:01: [io 0x0900-0x097f] has been reserved >> > system 00:01: [io 0x0980-0x09ff] has been reserved >> > system 00:01: [io 0x0a00-0x0a7f] has been reserved >> > system 00:01: [io 0x0a80-0x0aff] has been reserved >> > system 00:01: [io 0x0b00-0x0b7f] has been reserved >> > system 00:01: [io 0x0b80-0x0bff] has been reserved >> > system 00:01: [io 0x15e0-0x15ef] has been reserved >> > system 00:01: [io 0x1600-0x167f] has been reserved >> > system 00:01: [io 0x1640-0x165f] has been reserved >> > system 00:01: [mem 0xf8000000-0xfbffffff] could not be reserved >> > system 00:01: [mem 0xfed10000-0xfed13fff] has been reserved >> > system 00:01: [mem 0xfed18000-0xfed18fff] has been reserved >> > system 00:01: [mem 0xfed19000-0xfed19fff] has been reserved >> > system 00:01: [mem 0xfeb00000-0xfebfffff] has been reserved >> > system 00:01: [mem 0xfed20000-0xfed3ffff] has been reserved >> > system 00:01: [mem 0xfed90000-0xfed93fff] has been reserved >> > system 00:01: [mem 0xf7fe0000-0xf7ffffff] has been reserved >> > system 00:01: Plug and Play ACPI device, IDs PNP0c02 (active) >> > >> > Do you have firmware in the field that may not get updated? If so, >> > I'd like to see the whole solution for that firmware, including the >> > MCFG quirk (which tells the PCI core where the ECAM region is) and >> > whatever PNP0C02 quirk you figure out to actually reserve the region. >> > >> > I proposed a PNP0C02 quirk to Duc along these lines of the below. I >> > don't actually know if it's feasible, but it didn't look as bad as I >> > expected, so I'd kind of like somebody to try it out. I think you >> > would have to call this via a DMI hook (do you have DMI on arm64?), >> > maybe from pnp_init() or similar. >> >> We do have SMBIOS/DMI on arm64, but we have been successful so far not >> to rely on it for quirks, and we'd very much like to keep it that way. >> >> Since this ACPI _CRS method has nothing to do with SMBIOS/DMI, surely >> there is a better way to wire up the reservation code to the >> information exposed by ACPI? > > I'm open to other ways, feel free to propose one :) > > If you do a quirk, you need some way to identify the machine/firmware > combination, because you don't want to apply the quirk on every > machine. You're trying to work around a firmware issue, so you > probably want something tied to the firmware version. On x86, that's > typically done with DMI. > I think I misunderstood the purpose of the example: that should only be necessary if the _CRS methods are missing from the firmware, right? If we update the firmware to cover all non-enumerable resources by such a method, we shouldn't need any such quirks at all IIUC -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
