On Mon, 29 Jun, at 09:35:53AM, Josh Triplett wrote: > On Mon, Jun 29, 2015 at 05:44:58PM +0200, Borislav Petkov wrote: > > On Mon, Jun 29, 2015 at 03:49:40PM +0100, Matt Fleming wrote: > > > It still makes sense to have the error message because the kernel > > > literally does not know what the firmware is trying to achieve by > > > setting those bits. > > > > > > But I agree with Josh that for the specific case of "reserved bits", > > > FW_BUG is wrong, because if in some future version of the spec those > > > bits get used, seeing, > > > > > > "[Firmware Bug]: Ignoring BGRT: reserved bits are non-zero 0x3" > > > > I still don't see what that message brings if some kernel complains that > > some bits are !0 then. Are they valid bits which the kernel doesn't know > > about or are they erroneously set and reserved. This, IMHO, is confusing > > because the error message is not correct in all cases. > > > > Thus my suggestion to either check the spec version before looking at > > the bits or find out in some other way which bits are defined and which > > are reserved and warn only about the reserved ones which are 1b. > > The version is already checked *before* the status bits: if the version > is not 1, the kernel stops there and ignores the BGRT, before printing a > message about status. If we're performing version[1] checks then I think it's fair game to use FW_BUG, since these bits are reserved for that version. [1] Note the version of the BGRT table is checked, not the ACPI spec version, and it's not clear which would get a bump if new bits were defined for the 'status' field. Historically, new bits have been added to the EFI memory map without bumping the expected "memory descriptor" version - a spec version update was considered to be sufficient (see EFI_MEMORY_RO). -- Matt Fleming, Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
