• Dan Williams's avatar
    ahci: Add a generic 'controller2' RAID id · 5716fb0d
    Dan Williams authored
    Intel server platforms that support 'RAID', i.e. have platform firmware
    support for software-RAID metadata + features that the kernel also
    understands, maintain the same device-ids for RAID from generation to
    generation. This is in contrast to client platforms that have tended to
    roll new device-ids every platform generation. However, even though
    server platform keep the ids there are still unique device-ids per
    controller instance. To date there have only been 2 controllers on these
    platforms, but platforms code named Emmitsburg add a third controller.
    
    Add the device-id for this third controller and collect it with the
    other generic server RAID ids.
    
    As mentioned here [1], the pain of continuing add new and different
    device-ids for RAID mode to this file [2] has been heard. Ideally this
    device-id would not matter and the class code would remain
    PCI_CLASS_STORAGE_SATA_AHCI regardless of the RAID mode, but other
    operating systems depend on the class code *not* being AHCI when the
    device is in RAID mode. That said, going forward there is little reason
    for new server RAID ids to be added as they can simply reuse one of the
    existing ids even for a new controller. Server software RAID features
    continue to be supported on Linux. Client software RAID features
    continue to be not supported and the recommendation there remains to set
    the device to AHCI mode in platform firmware.
    
    Link: https://lore.kernel.org/all/8e61fb0104422e8d70701e2ddc7b1ca53f009797.camel@intel.com [1]
    Link: https://lore.kernel.org/all/20201119165022.GA3582@infradead.org/ [2]
    Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>
    Cc: Christoph Hellwig <hch@lst.de>
    Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
    Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
    Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
    Signed-off-by: default avatarDamien Le Moal <damien.lemoal@opensource.wdc.com>
    5716fb0d
ahci.c 63.3 KB