linux-kernel - Re: [PATCH] Quirk to fix suspend/resume on Lenovo Edge 11,13,14,15

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Message-ID: <AANLkTik7DgsmFv1KN6r92jai-Git5G9+kQLF9J0u=6e0@mail.gmail.com>
Date:	Fri, 14 Jan 2011 13:55:30 -0600
From:	Manoj Iyer <manoj.iyer@...onical.com>
To:	Borislav Petkov <bp@...64.org>
Cc:	Matthew Garrett <mjg59@...f.ucam.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"Herrmann3, Andreas" <Andreas.Herrmann3@....com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] Quirk to fix suspend/resume on Lenovo Edge 11,13,14,15

Borislav,

Any more thoughts on this one ?

Many Thanks
Manoj

On Thu, Jan 13, 2011 at 4:55 PM, Thomas Gleixner <tglx@...utronix.de> wrote:
> On Thu, 13 Jan 2011, Borislav Petkov wrote:
>> On Thu, Jan 13, 2011 at 04:30:43PM -0500, Thomas Gleixner wrote:
>> > The more interesting info is there in Manoj's logs:
>> >
>> > [    0.036455] ..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1
>> > [    0.040000] ..MP-BIOS bug: 8254 timer not connected to IO-APIC
>> > [    0.040000] ...trying to set up timer (IRQ0) through the 8259A ...
>> > [    0.040000] ..... (found apic 0 pin 0) ...
>> > [    0.080021] ....... works.
>> >
>> > versus
>> >
>> > [    0.036460] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
>> >
>> > So the "working" state is using "apic 0 pin 0" while the non working
>> > state is using "vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1".
>> >
>> > Something changes across suspend/resume which makes the BIOS
>> > advertised routing work with PIT but not with HPET. Further why does
>> > the apic 0/0 solution found by the kernel (when ignoring BIOS) works
>> > always (except that we don't know whether the "nohpet" case works as
>> > well, but I bet it does).
>>
>> Yes, it does. With "nohpet" we use PIT and PIT obviously works.
>
> No. We have no prove that acpi_skip_timer_override and nohpet work
> together :)
>
>> > So we are back to the question I raised above: What changes and even
>> > more interesting what changes after the HPET expires - which we know
>> > for sure that it must happen as otherwise we wont get a HPET interrupt
>> > after the 32bit wraparound.
>> >
>> > We need answers to these questions before applying any
>> > patch/workaround/quirk or whatever.
>>
>> Well, this is easily answered in the theoretical sense, without the
>> actual details :):
>>
>> 1. HPET gets reinitialized first
>> 2. Something programs it
>> 3. Timer expires but timer IRQ routing is still wrong and "Something"
>>    doesn't get its IRQ.
>> 4. Timer IRQ routing gets "fixed" as part of the resume path.
>>
>> ... we end up waiting for the counter to wraparound and get an IRQ which
>> gets delivered this time.
>>
>> Does that make sense at all?
>
> Yes, that's what I figured, but we need some explanation WHY this is
> "working" magically. Once we have that we can fix the issue at hand
> w/o applying random quirks.
>
> Thanks,
>
>        tglx
>



-- 
--manjo
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