4.16 OMAP serial transmit corruption?

[Russell King - ARM Linux]

On Mon, Apr 16, 2018 at 02:26:53PM -0700, Tony Lindgren wrote:
> * Tony Lindgren <tony at atomide.com> [180416 15:47]:
> > * Russell King - ARM Linux <linux at armlinux.org.uk> [180416 15:19]:
> > > Hi,
> > > 
> > > I'm not entirely sure what's going on, but I see corrupted characters
> > > with the serial console on the OMAP4430 SDP board.  During boot,
> > > everything seems fine, the problem appears to be userspace output.
> > > 
> > > For example, if I edit a file, then quit vi:
> > > 
> > > :q■■%■■B■■Z■root at omap-4430sdp:~#
> > 
> > I don't think I've seen that one. What I've seen few times is
> > typing a key on the serial console echoing back the previous
> > character typed while the new character won't get displayed
> > until hitting keyboard again. Only rebooting the device seems
> > to solve this. This is with 4430 ES2.3 revision.
> > 
> > I wonder if we're missing some parts of errata i202 handling
> > in omap_8250_mdr1_errataset()?
> 
> Trying to see what we might be missing in 8250_omap compared
> to omap-serial, your description sounds like it could be similar
> issue compared to what got fixed for omap-serial earlier with
> commit 0ba5f66836c9 ("tty: serial: OMAP: use a 1-byte RX FIFO
> threshold in PIO mode").

... except this is the transmit side, not the receive side.

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