Hi, On Tue, Dec 10, 2013 at 10:28:04PM +0000, James Hogan wrote: > From: James Hogan <james.ho...@imgtec.com> > > 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.ho...@imgtec.com> > Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> > Cc: Jiri Slaby <jsl...@suse.cz> > Cc: Tim Kryger <tim.kry...@linaro.org> > Cc: Ezequiel Garcia <ezequiel.gar...@free-electrons.com> > Cc: Matt Porter <matt.por...@linaro.org> > Cc: Markus Mayer <markus.ma...@linaro.org> > Cc: Heikki Krogerus <heikki.kroge...@linux.intel.com> > Tested-by: Tim Kryger <tim.kry...@linaro.org> > Tested-by: Ezequiel Garcia <ezequiel.gar...@free-electrons.com>
I tested this with HW without the busy functionality (UART_16550_COMPATIBLE == yes). No problems here. FWIW: Tested-by: Heikki Krogerus <heikki.kroge...@linux.intel.com> -- heikki -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
