Re: [PATCH 0/2] PCI/AER: Consistently use _OSC to determine who owns AER

From: Alex_Gagniuc
Date: Tue Nov 20 2018 - 17:36:33 EST


On 11/20/2018 04:08 PM, Sinan Kaya wrote:
> One version is:
> "if HEST table is present, ignore _OSC"
> or
> Another version is:
> "if HEST table is present, make sure that FW sets _OSC bit for AER to
> false. Otherwise, warn like crazy that this BIOS is broken and needs
> an update and can cause all sorts of trouble"

ACPI 6.2 Ch 6.2.11.3, Table 6-197
PCI Express Advanced Error Reporting control

The firmware sets this bit to 1 to grant control over PCI
Express Advanced Error Reporting.
If firmware allows the OS control of this feature, then in the
context of the _OSC method it must ensure that error messages
are routed to device interrupts as described in the PCI
Express Base Specification. Additionally, after control is
transferred to the OS, firmware must not modify the Advanced
Error Reporting Capability. If control of this feature was
requested and denied or was not requested, firmware returns
this bit set to 0.