• Mika Westerberg's avatar
    thunderbolt: Workaround an IOMMU fault on certain systems with Intel Maple Ridge · 582620d9
    Mika Westerberg authored
    On some systems the IOMMU blocks the first couple of driver ready
    messages to the connection manager firmware as can be seen in below
    excerpts:
    
      thunderbolt 0000:06:00.0: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0010 address=0xbb0e3400 flags=0x0020]
    
    or
    
      DMAR: DRHD: handling fault status reg 2
      DMAR: [DMA Write] Request device [04:00.0] PASID ffffffff fault addr 69974000 [fault reason 05] PTE Write access is not set
    
    The reason is unknown and hard to debug because we were not able to
    reproduce this locally. This only happens on certain systems with Intel
    Maple Ridge Thunderbolt controller. If there is a device connected when
    the driver is loaded the issue does not happen either. Only when there
    is nothing connected (so typically when the system is booted up).
    
    We can work this around by sending the driver ready several times. After
    a couple of retries the message goes through and the controller works
    just fine. For this reason make the number of retries a parameter for
    icm_request() and then for Maple Ridge (and Titan Ridge as they us the
    same function but this should not matter) increase number of retries
    while shortening the timeout accordingly.
    Reported-by: default avatarWerner Sembach <wse@tuxedocomputers.com>
    Reported-by: default avatarKonrad J Hambrick <kjhambrick@gmail.com>
    Reported-by: default avatarCalvin Walton <calvin.walton@kepstin.ca>
    Closes: https://bugzilla.kernel.org/show_bug.cgi?id=214259
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
    582620d9
icm.c 64.4 KB