From: Huang Ying <ying.huang@intel.com>
To: "Li, Shaohua" <shaohua.li@intel.com>
Cc: Myron Stowe <myron.stowe@hp.com>,
"lenb@kernel.org" <lenb@kernel.org>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
"ak@linux.intel.com" <ak@linux.intel.com>
Subject: Re: [PATCH 0/7] ACPI: Memory Mapped I/O (MMIO) pre-mapping
Date: Fri, 22 Oct 2010 10:57:00 +0800 [thread overview]
Message-ID: <1287716220.2862.57.camel@yhuang-dev> (raw)
In-Reply-To: <1287715387.8722.950.camel@sli10-conroe.sh.intel.com>
On Fri, 2010-10-22 at 10:43 +0800, Li, Shaohua wrote:
> On Fri, 2010-10-22 at 04:23 +0800, Myron Stowe wrote:
> > ACPI's system event related IRQ handing accesses specific fixed
> > hardware registers; namely PM1a event, PM1b event, GPE0, and GPE1
> > which are declared in the FADT. If these registers are backed by
> > MMIO, as opposed to I/O port space, accessing them within interrupt
> > context will incur a panic since acpi_read() and acpi_write() end up
> > calling ioremap(), which may block to allocate memory - BZ 18012.
> since you just access several bytes mmio in interrupt context, can't you
> use kmap_atomic_pfn() here?
On x86_64, kmap_atomic_pfn() is defined as kmap_atomic(), which requires
struct page for the physical address. But the MMIO address may have no
struct page.
Best Regards
Huang Ying
next prev parent reply other threads:[~2010-10-22 2:57 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-21 20:23 [PATCH 0/7] ACPI: Memory Mapped I/O (MMIO) pre-mapping Myron Stowe
2010-10-21 20:23 ` [PATCH 1/7] ACPI: Fix ioremap size for MMIO reads and writes Myron Stowe
2010-10-21 20:23 ` [PATCH 2/7] ACPI: Maintain a list of ACPI memory mapped I/O remappings Myron Stowe
2010-10-21 20:23 ` [PATCH 3/7] ACPI: Add interfaces for ioremapping/iounmapping ACPI registers Myron Stowe
2010-10-21 20:24 ` [PATCH 4/7] ACPI: Pre-map 'system event' related register blocks Myron Stowe
2010-10-21 20:24 ` [PATCH 5/7] ACPI: Convert simple locking to RCU based locking Myron Stowe
2010-10-21 20:24 ` [PATCH 6/7] ACPI: Page based coalescing of I/O remappings optimization Myron Stowe
2010-10-22 1:03 ` Huang Ying
2010-10-22 3:23 ` Myron Stowe
2010-10-22 5:17 ` Huang Ying
2010-10-22 16:27 ` Myron Stowe
2010-10-25 1:22 ` Huang Ying
2010-10-21 20:24 ` [PATCH 7/7] ACPI: Re-factor and remove ./drivers/acpi/atomicio.[ch] Myron Stowe
2010-10-22 2:43 ` [PATCH 0/7] ACPI: Memory Mapped I/O (MMIO) pre-mapping Shaohua Li
2010-10-22 2:57 ` Huang Ying [this message]
2010-10-22 3:16 ` Shaohua Li
2010-10-22 3:24 ` Huang Ying
2010-10-22 17:10 ` Bjorn Helgaas
2010-10-25 8:34 ` Andi Kleen
2010-10-25 8:43 ` Huang Ying
2010-10-25 9:29 ` Andi Kleen
2010-10-25 3:38 ` Len Brown
2010-10-25 15:34 ` Myron Stowe
2010-10-25 18:34 ` Andi Kleen
2010-10-28 1:53 ` Len Brown
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