Hi Fabio, On Thu, May 15, 2014 at 03:14:36PM -0300, Fabio Estevam wrote: > Bit 7 of UCR3 is described in the i.MX reference manuals (with the exception > of i.MX1) as follows: > > ADNIMP: Autobaud Detection Not Improved-. Disables new features of > autobaud detection (See Baud Rate Automatic Detection > Protocol, for more details). > > 0 Autobaud detection new features selected > 1 Keep old autobaud detection mechanism > > The "new features" mechanism occasionally causes the receiver to get out of sync > and continuously produces received characters of '0xff'. > > In order to reproduce the problem: > > $ cs0.baudrate=19200 > - Change the terminal baudrate to 19200 > - Type in the console and it should look good > - Change the terminal baudrate back to 115200 > - Type 'b' in the console, then a stream of '0xff' is transmitted in loop > > Setting the ADNIMP bit avoids the transmission of '0xff' in loop. > > Also rename the bit definition as per the reference manual. > > Tested on mx6q. > > Based on a patch from Eric Nelson for U-boot. > > Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxxxxxxxx> > --- > As the 0xff character is not seen in the console, an easy way to 'see' it is > doing like this in order to easily demonstrate the bug: > > --- a/drivers/serial/serial_imx.c > +++ b/drivers/serial/serial_imx.c > @@ -258,7 +258,8 @@ static int imx_serial_getc(struct console_device *cdev) > while (readl(priv->regs + priv->devtype->uts) & UTS_RXEMPTY); > > ch = readl(priv->regs + URXD0); > - > + if (ch >= 0x80) > + ch = '?'; This is not part of the fix, right? Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
