• Elric Fu's avatar
    xHCI: add aborting command ring function · b92cc66c
    Elric Fu authored
    Software have to abort command ring and cancel command
    when a command is failed or hang. Otherwise, the command
    ring will hang up and can't handle the others. An example
    of a command that may hang is the Address Device Command,
    because waiting for a SET_ADDRESS request to be acknowledged
    by a USB device is outside of the xHC's ability to control.
    
    To cancel a command, software will initialize a command
    descriptor for the cancel command, and add it into a
    cancel_cmd_list of xhci.
    
    Sarah: Fixed missing newline on "Have the command ring been stopped?"
    debugging statement.
    
    This patch should be backported to kernels as old as 3.0, that contain
    the commit 7ed603ec "xhci: Add an
    assertion to check for virt_dev=0 bug." That commit papers over a NULL
    pointer dereference, and this patch fixes the underlying issue that
    caused the NULL pointer dereference.
    Signed-off-by: default avatarElric Fu <elricfu1@gmail.com>
    Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
    Tested-by: default avatarMiroslav Sabljic <miroslav.sabljic@avl.com>
    Cc: stable@vger.kernel.org
    b92cc66c
xhci.h 62.9 KB