Re: [PATCH V2 1/1] USB: serial: f81232: fix incomplete serial port generation

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

Hi,

Johan Hovold 於 2025/12/1 下午 09:38 寫道:
> On Fri, Nov 28, 2025 at 04:52:44PM +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.
>>
>> 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.
>>
>> Tested on: HygonDM1SLT(Hygon C86 3250 8-core Processor)
>>
>> Signed-off-by: Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>
>> ---
>> Changelog:
>> v2:
>> 	1. remove loop in accessor function.
> Thanks for verifying.
>
> Did you try removing the retry loop also in the set_register() helper?
> Perhaps that's no longer needed after the dummy read.

I will try removing the retry loop in set_register() helper.
If that worked, could I use the same patch file or series of patches?

Thanks,


-- 

*洪繼澤 **Peter Hong*

精拓科技股份有限公司

Feature Integration Technology

Address: 302新竹縣竹北市台元二街10號7樓

TEL: 03-5600168 #813

FAX: 03-5600166

E-Mail﹕peter_hong@fintek.com.tw