On Thu, Mar 01, 2018 at 01:15:28PM +0200, Mathias Nyman wrote: > Disabing Latency Tolerance Messaging before port reset is unnecessary. > LTM is automatically disabled at port reset. > > If host can't communicate with the device the LTM message will fail, and > the hub driver will unnecessarily do a logical disconnect. > Broken communication is ofter the reason for a reset in the first place. > > Additionally we can't guarantee device is in a configured state, > epecially in reset-resume case when root hub lost power. > LTM can't be modified unless device is in a configured state. > > Just remove LTM disabling before port reset. > > Details about LTM and port reset in USB 3 specification: > > USB 3 spec section 9.4.5 > "The LTM Enable field can be modified by the SetFeature() and > ClearFeature() requests using the LTM_ENABLE feature selector. > This field is reset to zero when the device is reset." > > USB 3 spec section 9.4.1 > "The device shall process a Clear Feature (U1_Enable or U2_Enable or > LTM_Enable) only if the device is in the configured state." > > Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> > --- > drivers/usb/core/hub.c | 12 +++--------- > 1 file changed, 3 insertions(+), 9 deletions(-) Is this causing problems now such that we should get this to older kernels as well? 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
