On Mon, Jun 29, 2015 at 03:49:40PM +0100, Matt Fleming wrote: > On Mon, 29 Jun, at 04:17:24PM, Borislav Petkov wrote: > > On Mon, Jun 29, 2015 at 07:00:22AM -0700, Josh Triplett wrote: > > > Definitely not FW_BUG. The field is reserved *now*; it would be > > > legitimate for a new version of the BGRT spec to define one of those > > > bits for something else. > > > > Which would mean that booting old kernels on new FW which defines those > > reserved bits would cause that warning to fire erroneously. > > > > So then we probably don't need it at all or we need to check implemented > > BGRT version of the FW running to know which bits are defined by the > > spec and which are reserved... > > 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" > > is going to confuse the hell outta any firmware engineers, since it's > not the firmware that's buggy, it's just that the kernel lacks support. Right. Same reason we shouldn't use FW_BUG for bgrt_tab->version != 1 or bgrt_tab->image_type != 0 . > This discussion should definitely be summarised in printk.h. > > However, other error messages in efi-bgrt.c probably do want to be > sprinkled with FW_* if they represent things that should never happen > ever. I think the length check and null pointer check would fall in that category. - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
