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Date: Mon, 11 Jul 2011 13:23:18 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Takao Indoh <indou.takao@jp.fujitsu.com>
Cc: linux-kernel@vger.kernel.org, amwang@redhat.com, ebiederm@xmission.com,
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Subject: Re: [PATCH v2] acpi: introduce "acpi_rsdp=" parameter for kdump
Message-ID: <20110711172318.GA18279@dumpdata.com>
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On Mon, Jul 11, 2011 at 11:14:41AM -0400, Takao Indoh wrote:
> Revised version of the patch which was posted by Cong WANG
> 
> v1:
> https://lkml.org/lkml/2011/3/10/206
> 
> There is a problem with putting the first kernel in EFI virtual mode,
> it is that when the second kernel comes up it tries to initialize the
> EFI again and once we have put EFI in virtual mode we can not really
> do that.
> 
> Actually, EFI is not necessary for kdump, we can boot the second kernel
> with "noefi" parameter, but the boot will mostly fail because 2nd kernel
> cannot find RSDP.
> 
> In this situation, we introduced "acpi_rsdp=" kernel parameter, so that
> kexec-tools can pass the "noefi acpi_rsdp=X" to the second kernel to make
> kdump works.
> 
> Changes in v2:
> * Change parameter name from "acpi_addr" to "acpi_rsdp"
> * Add CONFIG_KEXEC

How will the tools get the physical address of the RSDP?