On Wed, Jul 31, 2013 at 11:30:28AM -0700, Sarah Sharp wrote: > From: Julius Werner <jwerner@xxxxxxxxxxxx> > > The USB hub driver's event handler contains a check to catch SuperSpeed > devices that transitioned into the SS.Inactive state and tries to fix > them with a reset. It decides whether to do a plain hub port reset or > call the usb_reset_device() function based on whether there was a device > attached to the port. > > However, there are device/hub combinations (found with a JetFlash > Transcend mass storage stick (8564:1000) on the root hub of an Intel > LynxPoint PCH) which can transition to the SS.Inactive state on > disconnect (and stay there long enough for the host to notice). In this > case, above-mentioned reset check will call usb_reset_device() on the > stale device data structure. The kernel will send pointless LPM control > messages to the no longer connected device address and can even cause > several 5 second khubd stalls on some (buggy?) host controllers, before > finally accepting the device's fate amongst a flurry of error messages. > > This patch makes the choice of reset dependent on the port status that > has just been read from the hub in addition to the existence of an > in-kernel data structure for the device, and only proceeds with the more > extensive reset if both are valid. > > Signed-off-by: Julius Werner <jwerner@xxxxxxxxxxxx> > Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> > --- > drivers/usb/core/hub.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Should this patch also go to the stable kernel releases? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
