Regression: serial: imx: overrun errors on debug UART

[Uwe Kleine-König]

On Fri, Mar 24, 2023 at 03:19:46PM +0100, Stefan Wahren wrote:
> Hi,
> 
> Am 24.03.23 um 14:37 schrieb Uwe Kleine-König:
> > On Fri, Mar 24, 2023 at 09:57:39AM -0300, Fabio Estevam wrote:
> > > Hi Stefan,
> > > 
> > > On Fri, Mar 24, 2023 at 8:48 AM Ilpo Järvinen
> > > <ilpo.jarvinen at linux.intel.com> wrote:
> > > 
> > > > This has come up earlier, see e.g.:
> > > > 
> > > > https://lore.kernel.org/linux-serial/20221003110850.GA28338@francesco-nb.int.toradex.com/
> > > > 
> > > > My somewhat uninformed suggestion: if the overrun problems mostly show up
> > > > with console ports, maybe the trigger level could depend on the port
> > > > being a console or not?
> > > Does the change below help? Taking Ilpo's suggestion into account:
> > I wonder if it's a red herring that having the console on that port
> > makes a difference. If I understand correctly the problem is pasting
> > bigger amounts of data on a ttymxc after having logged in via a getty?
> > 
> > @Stefan: Can you try to reproduce with the port being also a console?
> 
> Sorry, for the confusion. Maybe i should have mentioned that the debug UART
> was configured as a console. Here is the output to be more specific (ttymxc0
> and 4 are RS485, ttymxc3 is the debug console):
> 
> # cat /proc/tty/driver/IMX-uart
> 
> serinfo:1.0 driver revision:
> 0: uart:IMX mmio:0x02020000 irq:192 tx:285207 rx:2633621 fe:2 DSR|CD
> 3: uart:IMX mmio:0x021F0000 irq:193 tx:70502 rx:69 RTS|DTR|DSR
> 4: uart:IMX mmio:0x021F4000 irq:194 tx:300988 rx:677223 DSR|CD
> 5: uart:IMX mmio:0x021FC000 irq:195 tx:0 rx:0 DSR|CD
> 6: uart:IMX mmio:0x02018000 irq:191 tx:0 rx:0 DSR|CD
> 
> Just for clarification the Tarragon board is build in a charging station. So
> hardware access is limited.
> 
> @Uwe which port should be configured as a console?

I don't care as long as it's not hte port that you do your test on. None
is fine.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |
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