From: Ingo Molnar <mingo@kernel.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: "Wang, Song-Bo (Stoney)" <song-bo.wang@hp.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
"Zhang, Lin-Bao (Linux Kernel R&D)" <linbao.zhang@hp.com>,
"Pearson, Greg" <greg.pearson@hp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"suresh.b.siddha@intel.com" <suresh.b.siddha@intel.com>
Subject: Re: [PATCH] x86/apic: check FADT settings after enable x2apic
Date: Mon, 28 Jan 2013 11:11:35 +0100 [thread overview]
Message-ID: <20130128101135.GD7168@gmail.com> (raw)
In-Reply-To: <CAE9FiQW75eP_exufb1gd7jQuu98WnkyGX23EBXktUCSyZX9Jvg@mail.gmail.com>
* Yinghai Lu <yinghai@kernel.org> wrote:
> On Sun, Jan 27, 2013 at 9:05 PM, Wang, Song-Bo (Stoney)
> <song-bo.wang@hp.com> wrote:
> > Hi Yinghai, hpa and others,
> >
> > Would you please review the patch on detecting x2apic FADT settings?
> >
> > We meet a BIOS system which works on x2apic physical mode by
> > setting the bit ACPI_FADT_APIC_PHYSICAL in FADT table. And
> > for those systems with all cpuid < 255, the spec requires
> > BIOS's default mode in xapic. The kernel detects the default
> > mode and do some initializations and will call
> > enable_IR_x2apic and change the mode to x2apic successfully.
>
> Hi, Peter and Ingo,
>
> I checked the patch, and looks right.
>
> I updated the changelog and simplify the code a little bit.
>
> Please check if you can put it into tip:x86/apic
The code looks good to me, but the changelog is still lacking:
> HP has systems that work with x2apic phys mode and BIOS set
> ACPI_FADT_APIC_PHYSICAL in FADT table, and all cpuid < 255,
> the spec requires BIOS only put system on xapic mode. Kernel
Which spec?
> will set to x2apic logical mode instead of x2apic phys mode.
Which has exactly what bad effect on users of these systems?
You left out the most important information from the changelog:
why do users care, what good does the patch do?
Thanks,
Ingo
next prev parent reply other threads:[~2013-01-28 10:11 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-15 1:50 [PATCH] x86/apic: check FADT settings after enable x2apic Stoney Wang
2013-01-28 5:05 ` Wang, Song-Bo (Stoney)
2013-01-28 6:57 ` Yinghai Lu
2013-01-28 10:11 ` Ingo Molnar [this message]
2013-01-28 18:10 ` Yinghai Lu
2013-01-29 7:47 ` Ingo Molnar
2013-01-29 8:43 ` Wang, Song-Bo (Stoney)
2013-01-29 8:49 ` Ingo Molnar
2013-01-29 21:30 ` Yinghai Lu
2013-01-29 21:52 ` Yinghai Lu
2013-01-31 11:32 ` Ingo Molnar
2013-01-31 15:56 ` Yinghai Lu
2013-02-04 6:41 ` Wang, Song-Bo (Stoney)
2013-02-04 11:03 ` Ingo Molnar
2013-02-04 20:29 ` [PATCH] x86, apic: Check fadt x2apic phys in x2apic_phys_probe() Yinghai Lu
2013-02-05 12:24 ` Ingo Molnar
2013-02-05 16:53 ` Yinghai Lu
2013-02-06 13:16 ` Ingo Molnar
2013-02-06 17:10 ` Yinghai Lu
2013-02-07 18:53 ` [PATCH v4] " Yinghai Lu
2013-02-11 12:37 ` [tip:x86/urgent] x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems tip-bot for Stoney Wang
2013-02-18 8:52 ` [PATCH v4] x86, apic: Check fadt x2apic phys in x2apic_phys_probe() Lin-Bao Zhang
2013-02-18 17:13 ` Yinghai Lu
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