Regression: serial: imx: overrun errors on debug UART

[Stefan Wahren]

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?

>
> Best regards
> Uwe
>
>
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