Re: [PATCH v2] tty: serial: msm: Don't reconfigure same baud rate

From: Nicolas Dechesne
Date: Fri Jun 17 2016 - 06:03:12 EST


On Thu, Jun 16, 2016 at 9:24 PM, Bjorn Andersson
<bjorn.andersson@xxxxxxxxxx> wrote:
> msm_set_termios() is called whenever the tty is opened. Setting the baud
> rate requires a full reset of the msm serial block, even when the rate
> is unchanged. In the case when the same uart is used as console this
> reset will discard any console output data still being clocked out of
> the TX fifo.
>
> By skipping the rate-change in the case where the baud rate is unchanged
> since last request we can avoid the reset and the discarding of the
> data.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>


Tested-by: Nicolas Dechesne <nicolas.dechesne@xxxxxxxxxx>

I no longer see this type of corruption on serial console

[ 6.325118] ALSA device ï[ 6.333338] Freeing unused kernel
memory: 572K (ffffffc000c10000 - ffffffc000c9f000)
[ 13.800269] remoteproc2: remote processor a20400ï[ OK ] Started
Start the WCN core.
[ ï Starting Update UTMP about System Runlevel Changes...