From: Johan Hovold <johan@kernel.org>
To: "Ji-Ze Hong (Peter Hong)" <peter_hong@fintek.com.tw>
Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org, tom_tsai@fintek.com.tw,
yu_chen@fintek.com.tw, hpeter+linux_kernel@gmail.com
Subject: Re: [PATCH V1 1/1] USB: serial: f81232: fix incomplete serial port generation
Date: Tue, 14 Oct 2025 17:36:33 +0200 [thread overview]
Message-ID: <aO5uAUknTLOWdvUY@hovoldconsulting.com> (raw)
In-Reply-To: <20251008023858.227740-1-peter_hong@fintek.com.tw>
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)?
> 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?
Johan
next prev parent reply other threads:[~2025-10-14 15:36 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-08 2:38 [PATCH V1 1/1] USB: serial: f81232: fix incomplete serial port generation Ji-Ze Hong (Peter Hong)
2025-10-14 15:36 ` Johan Hovold [this message]
2025-10-15 2:24 ` Peter Hong
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