• Andiry Xu's avatar
    USB: EHCI: AMD periodic frame list table quirk · 3d091a6f
    Andiry Xu authored
    On AMD SB700/SB800/Hudson-2/3 platforms, USB EHCI controller may read/write
    to memory space not allocated to USB controller if there is longer than
    normal latency on DMA read encountered. In this condition the exposure will
    be encountered only if the driver has following format of Periodic Frame
    List link pointer structure:
    
    For any idle periodic schedule, the Frame List link pointers that have the
    T-bit set to 1 intending to terminate the use of frame list link pointer
    as a physical memory pointer.
    
    Idle periodic schedule Frame List Link pointer shoule be in the following
    format to avoid the issue:
    
    Frame list link pointer should be always contains a valid pointer to a
    inactive QHead with T-bit set to 0.
    Signed-off-by: default avatarAndiry Xu <andiry.xu@amd.com>
    Acked-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
    3d091a6f
ehci-mem.c 6.73 KB