• Matt Domsch's avatar
    PCI: PCIe AER: honor ACPI HEST FIRMWARE FIRST mode · 05843961
    Matt Domsch authored
    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.
    Reviewed-by: default avatarKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
    Reviewed-by: default avatarHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
    Signed-off-by: default avatarMatt Domsch <Matt_Domsch@dell.com>
    Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
    05843961
acpi_hest.h 253 Bytes