Re: [PATCH] PCIe AER: honor ACPI HEST FIRMWARE FIRST mode

[Jesse Barnes]

On Mon, 2 Nov 2009 11:51:24 -0600
Matt Domsch <Matt_Domsch@xxxxxxxx> wrote:

> From 97ec121f91e5c76dc037f8d2abaea84c5476676e Mon Sep 17 00:00:00 2001
> From: Matt Domsch <Matt_Domsch@xxxxxxxx>
> Date: Thu, 8 Oct 2009 23:18:11 -0500
> Subject: [PATCH] PCIe AER: honor ACPI HEST FIRMWARE FIRST mode
> 
> Feedback from Hidetoshi Seto and Kenji Kaneshige incorporated.  This
> correctly handles PCI-X bridges, PCIe root ports and endpoints, and
> prints debug messages when invalid/reserved types are found in the
> HEST.  PCI devices not in domain/segment 0 are not represented in
> HEST, thus will be ignored.
> 
> Today, the PCIe Advanced Error Reporting (AER) driver attaches itself
> to every PCIe root port for which BIOS reports it should, via ACPI
> _OSC.
> 
> However, _OSC alone is insufficient for newer BIOSes.  Part of ACPI
> 4.0 is the new APEI (ACPI Platform Error Interfaces) which is a way
> for OS and BIOS to handshake over which errors for which components
> each will handle.  One table in ACPI 4.0 is the Hardware Error Source
> Table (HEST), where BIOS can define that errors for certain PCIe
> devices (or all devices), should be handled by BIOS ("Firmware First
> mode"), rather than be handled by the OS.
> 
> Dell PowerEdge 11G server BIOS defines Firmware First mode in HEST, so
> that it may manage such errors, log them to the System Event Log, and
> possibly take other actions.  The aer driver should honor this, and
> not attach itself to devices noted as such.
> 
> Furthermore, Kenji Kaneshige reminded us to disallow changing the AER
> registers when respecting Firmware First mode.  Platform firmware is
> expected to manage these, and if changes to them are allowed, it could
> break that firmware's behavior.
> 
> The HEST parsing code may be replaced in the future by a more
> feature-rich implementation.  This patch provides the minimum needed
> to prevent breakage until that implementation is available.
> 
> Signed-off-by: Matt Domsch <Matt_Domsch@xxxxxxxx>
> ---

Applied to my linux-next branch, thanks.

Jesse
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