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  • David Brownell's avatar
    USB: add ehci_hcd.ignore_oc parameter · 93f1a47c
    David Brownell authored
    
    
    Certain boards seem to like to issue false overcurrent notifications, for
    example on ports that don't have anything connected to them.  This looks
    like a hardware error, at the level of noise to those ports' overcurrent
    input signals (or non-debounced VBUS comparators).  This surfaces to users
    as truly massive amounts of syslog spam from khubd (which is appropriate
    for real hardware problems, except for the volume from multiple ports).
    
    Using this new "ignore_oc" flag helps such systems work more sanely, by
    preventing such indications from getting to khubd (and spam syslog).  The
    downside is of course that true overcurrent errors will be masked; they'll
    appear as spontaneous disconnects, without the diagnostics that will let
    users troubleshoot issues like short circuited cables.
    
    Note that the bulk of these reports seem to be with VIA southbridges, but
    I think some were with Intel ones.
    
    Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
    93f1a47c