Re: [Linaro-acpi] [PATCH v5 0/5] Provide better MADT subtable sanity checks

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Monday, October 12, 2015 03:04:30 PM Hanjun Guo wrote:
> On 10/12/2015 11:58 AM, Pat Erley wrote:
> > On 10/11/2015 08:49 PM, Hanjun Guo wrote:
> >> On 10/12/2015 11:08 AM, Pat Erley wrote:
> >>> On 10/05/2015 10:12 AM, Al Stone wrote:
> >>>> On 10/05/2015 07:39 AM, Rafael J. Wysocki wrote:
> >>>>> On Wednesday, September 30, 2015 10:10:16 AM Al Stone wrote:
> >>>>>> On 09/30/2015 03:00 AM, Hanjun Guo wrote:
> >>>>>>> On 2015/9/30 7:45, Al Stone wrote:
> >>>>>>>> NB: this patch set is for use against the linux-pm bleeding edge
> >>>>>>>> branch.
> >>>>>>>>
> >>>>>>
> >>>>>> [snip...]
> >>>>>>
> >>>>>>>
> >>>>>>> For this patch set,
> >>>>>>>
> >>>>>>> Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
> >>>>>>>
> >>>>>>> Thanks
> >>>>>>> Hanjun
> >>>>>>
> >>>>>> Thanks, Hanjun!
> >>>>>
> >>>>> Series applied, thanks!
> >>>>>
> >>>>> Rafael
> >>>>>
> >>>>
> >>>> Thanks, Rafael!
> >>>>
> >>>
> >>> Just decided to test out linux-next (to see the new nouveau cleanups).
> >>> This change set prevents my Lenovo W510 from booting properly.
> >>>
> >>> Reverting: 7494b0 "ACPI: add in a bad_madt_entry() function to
> >>> eventually replace the macro"
> >>>
> >>> Gets the system booting again.  I'm attaching my dmesg from the failed
> >>> boot, who wants the acpidump?
> >>
> >> [    0.000000] ACPI: undefined version for either FADT 4.0 or MADT 1
> >> [    0.000000] ACPI: Error parsing LAPIC address override entry
> >> [    0.000000] ACPI: Invalid BIOS MADT, disabling ACPI
> >>
> >> Seems the MADT revision is not right, could you dump the ACPI MADT
> >> (APIC) table and send it out? I will take a look :)
> >>
> >> Thanks
> >> Hanjun
> >
> > Here ya go, enjoy.  Feel free to CC me on any patches that might fix it.
> 
> Thanks! I think I had the right guess, the MADT revision is not right
> for ACPI 4.0:
> 
> [000h 0000   4]                    Signature : "APIC"    [Multiple APIC 
> Description Table (MADT)]
> [004h 0004   4]                 Table Length : 000000BC
> [008h 0008   1]                     *Revision : 01*
> 
> I encountered such problem before because the table was just copied from
> previous version, and without the update for table revision.
> 
> I think we may need to ignore the table revision for x86, but restrict
> it for ARM64, I'd like Al and Rafael's suggestion before I send out a
> patch.

As I said before to Al, we definitely can't break systems that worked before
the commit in question.

Thanks,
Rafael