Hi, On Tue, Dec 10, 2013 at 10:28:04PM +0000, James Hogan wrote: > From: James Hogan <james.hogan@xxxxxxxxxx> > > Commit c49436b657d0 (serial: 8250_dw: Improve unwritable LCR workaround) > caused a regression. It added a check that the LCR was written properly > to detect and workaround the busy quirk, but the behaviour of bit 5 > (UART_LCR_SPAR) differs between IP versions 3.00a and 3.14c per the > docs. On older versions this caused the check to fail and it would > repeatedly force idle and rewrite the LCR register, causing delays and > preventing any input from serial being received. > > This is fixed by masking out UART_LCR_SPAR before making the comparison. > > Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Cc: Jiri Slaby <jslaby@xxxxxxx> > Cc: Tim Kryger <tim.kryger@xxxxxxxxxx> > Cc: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxxxxxxxxxx> > Cc: Matt Porter <matt.porter@xxxxxxxxxx> > Cc: Markus Mayer <markus.mayer@xxxxxxxxxx> > Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > Tested-by: Tim Kryger <tim.kryger@xxxxxxxxxx> > Tested-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxxxxxxxxxx> I tested this with HW without the busy functionality (UART_16550_COMPATIBLE == yes). No problems here. FWIW: Tested-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> -- heikki -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
