Wait, I thought it had to be 4 characters. ron
On Fri, Apr 22, 2016 at 2:36 PM Aaron Durbin via coreboot < [email protected]> wrote: > On Fri, Apr 22, 2016 at 2:00 PM, Duncan Laurie <[email protected]> > wrote: > > On Tue, Apr 19, 2016 at 6:49 AM, Aaron Durbin <[email protected]> > wrote: > >> > >> On Mon, Apr 18, 2016 at 10:17 PM, Julius Werner <[email protected]> > >> wrote: > >> > I think we should only export the coreboot table location and size > >> > through ACPI and then read everything else from there. That way we can > >> > share almost all of the kernel driver code with ARM and just need a > >> > tiny platform-specific stub to look up the table location first. If we > >> > add all the information into an actual ACPI table, we're building an > >> > x86-only solution again. (A generic, platform-independent coreboot > >> > driver could just as easily export the stuff we want into sysfs.) > >> > > >> > >> That's fine. The only thing I was concerned about was implementing an > >> ACPI table proper or try to do some ACPI device shenanigans like the > >> ramoops device. coreboot doesn't currently have a ACPI ID assigned to > >> it. If we go with a ACPI device coreboot should apply for an ACPI ID. > >> I personally think the coreboot ACPI table seems more straight > >> forward, but I was wondering if people knew of any downsides to going > >> that route. > >> > > > > > > The official tables are all defined in the ACPI spec while the related > > tables are also linked to from the spec, so we'd need to convince the > UEFI > > forum to at least reserve the signature for us (and then link to our > table > > definition) since they intend to act as gatekeepers to avoid collisions > in > > table signatures: > > > > "Requests to reserve a 4-byte alphanumeric table signature should be > sent to > > the email address [email protected] and should include the purpose of the > table > > and reference URL to a document that describes the table format." > > > > An easier path would be to define a specific device in the DSDT and > populate > > it with the various data we want to be there on every system. That would > > allow us to control the format and be able to alter it in the future if > we > > want to expose new information. > > > > As you note a Device would need a valid unique HID, and that needs an ID > > prefix if it wants to be official. In theory we could request something > > like "CORE" as an official APCI ID from > > http://www.uefi.org/PNP_ACPI_Registry > > OK. Time for bikeshedding: > > 1. CORE > 2. CBOOT > 3. ... ? > > Stefan, we'll likely need you to request the HID w/ your coreboot.org > email. > > > > > I suppose the real difference between the two is whether we need this > data > > early in boot before there is an AML interpreter available in the OS. > > I don't think we need it that early. Right now the current usage (at > least on x86) is all very late since we're doing AML evaluation. We > could go w/ the ACPI device first. Just need to request that HID. > > > > > -duncan > > > > > > -- > > coreboot mailing list: [email protected] > > https://www.coreboot.org/mailman/listinfo/coreboot > > -- > coreboot mailing list: [email protected] > https://www.coreboot.org/mailman/listinfo/coreboot >
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