Messages in this thread |  | | | From | (Eric W. Biederman) | | Date | Wed, 18 Jun 2008 21:32:01 -0700 | | Subject | Re: [PATCH] x86: update mptable v7 |
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"Yinghai Lu" <yhlu.kernel@gmail.com> writes:
> On Wed, Jun 18, 2008 at 5:33 PM, Len Brown <lenb@kernel.org> wrote: >> >> >> On Wed, 18 Jun 2008, Yinghai Lu wrote: >> >>> On Wed, Jun 18, 2008 at 3:18 PM, Len Brown <lenb@kernel.org> wrote: >>> > >>> > >>> > On Sun, 1 Jun 2008, Yinghai Lu wrote: >>> > >>> >> >>> >> make mptable to be consistent to acpi routing, so we could >>> >> 1. kexec kernel with acpi=off >>> >> 2. workaround BIOS that acpi routing is working, but mptable is not right. >>> >> so can use kernel/kexec to start other os that doesn't have good acpi > support >>> > >>> > Is this an effort to boot an ACPI-mode kernel, >>> > and then kexec a non-ACPI kernel? >>> >>> Yes, >> >> Why is this feature needed? >> There are a number of ways that the resulting kernel may fail, >> all platform specific. > > other os still doesn't have update acpi irq routing support. but has > broken mptable.
Which is at least in part a reason to go back to the BIOS manufacturer and get them to fix their table.
I can see a warning coming from the kernel if these two tables are inconsistent though.
>>> > Doing so could confuse the heck out of the platform firmware, >>> > which will think that an ACPI-mode kernel is still running. >>> > >>> > Note that it is a historic artifact, now considered a bug, >>> > that ACPI uses the MPS code. We should be divorcing these >>> > two bodies of code rather than mixing them further. >>> >>> how about adding config option to not compile mptable related info? >> >> That's the idea. >> CONFIG_MPS=n CONFIG_ACPI=y should build and run on >> every PC built in this century. >> >> This was prototyped a long while back, but the >> tree has churned so much since then the old >> prototype is worthless. > > will look at it tonight. > > when EFI is popular, there is no reason to compile mps related stuff > in kernel again. esp for 64 bit.
? EFI has nothing to do with this. ACPI is popular today and EFI preserves EFI.
> BTW, it is funny that Suse still has fallsafe boot entry with acpi=off.
Silly question. Given that even writing to this table is platform specific. Any chance we can do this any a userspace utility writing through /dev/mem for the systems that need it? We can even bundle the utility in the kexec-tools package to make it easier to distribute.
Eric
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