• Tejun Heo's avatar
    libata: fix unexpectedly frozen port after ata_eh_reset() · 8c56cacc
    Tejun Heo authored
    To work around controllers which can't properly plug events while
    reset, ata_eh_reset() clears error states and ATA_PFLAG_EH_PENDING
    after reset but before RESET is marked done.  As reset is the final
    recovery action and full verification of devices including onlineness
    and classfication match is done afterwards, this shouldn't lead to
    lost devices or missed hotplug events.
    
    Unfortunately, it forgot to thaw the port when clearing EH_PENDING, so
    if the condition happens after resetting an empty port, the port could
    be left frozen and EH will end without thawing it, making the port
    unresponsive to further hotplug events.
    
    Thaw if the port is frozen after clearing EH_PENDING.  This problem is
    reported by Bruce Stenning in the following thread.
    
     http://thread.gmane.org/gmane.linux.kernel/1123265
    
    stable: I think we should weather this patch a bit longer in -rcX
    	before sending it to -stable.  Please wait at least a month
    	after this patch makes upstream.  Thanks.
    
    -v2: Fixed spelling in the comment per Dave Howorth.
    Signed-off-by: default avatarTejun Heo <tj@kernel.org>
    Reported-by: default avatarBruce Stenning <b.stenning@indigovision.com>
    Cc: stable@kernel.org
    Cc: Dave Howorth <dhoworth@mrc-lmb.cam.ac.uk>
    Signed-off-by: default avatarJeff Garzik <jgarzik@pobox.com>
    8c56cacc
libata-eh.c 106 KB