[PATCH v2] serial: imx: Fix buggy transmissions when baudrate mismatches
s.hauer at pengutronix.de
Mon Jun 2 23:42:17 PDT 2014
On Mon, Jun 02, 2014 at 11:06:39AM -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 at freescale.com>
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