Re: [PATCH V1 1/1] USB: serial: f81232: fix incomplete serial port generation

[Peter Hong <peter_hong@fintek.com.tw>]

Hi Johan,

Johan Hovold 於 2025/10/14 下午 11:36 寫道:
> On Wed, Oct 08, 2025 at 10:38:58AM +0800, Ji-Ze Hong (Peter Hong) wrote:
>> The Fintek F81532A/534A/535/536 family relies on the
>> F81534A_CTRL_CMD_ENABLE_PORT (116h) register during initialization to
>> both determine serial port status and control port creation. If the
>> driver experiences fast load/unload cycles, the device state may becomes
>> unstable, resulting in the incomplete generation of serial ports.
> Do I understand correctly that you're only seeing this issue if you're
> unloading and reloading the module (or rebinding the driver through
> sysfs)?

Yes, this issue has only been observed and reported during module unload
and reload operations currently.

>> Performing a dummy read operation on the register prior to the initial
>> write command resolves the issue. This clears the device's stale internal
>> state. Subsequent write operations will correctly generate all serial
>> ports.
> Does this mean that the retry loop is no longer needed? Can it now be
> removed in either or both accessor functions perhaps?

OK, we'll test the loop removal in the accessor. If successful, we'll prepare
and send V2.


Thanks,