From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1CC1B253B58; Mon, 1 Dec 2025 13:38:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764596285; cv=none; b=O488KmZTfbxI1+7cnL5yDnLOwG8Mt05eO+iV7eXR/GlKPB2JOF43mrrY3KAvHgoMPe3Qj8gRpeyCzxpr50fMb2krms7r/xY2m7qRwP3k6LzUbFDrEeBs5nvfNuFjwsYfBHRgnG4tSmBwwHkqIDxCCNSjg/YUgj1jBpW20Ejd2Mw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764596285; c=relaxed/simple; bh=Z70NDaPe+lKHzewSCi3t9HKBO5LDjbDqeteLg/sp2yo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nw+a+baKdiyXQhOGkXNNb8d/9jUgRc2P/tnegv7LI5nJtsnIfBf6dK/eJ/8RDlE11ay2mswbtBmB4vztwTnJgUf5O0XmThnwUYatfIYCRah//bvNBy/TRD9Zw5YCaq6PUE7uKy1JDONdTdJlszpSk3YdSd9VewRsplpj+ctGXqM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eI6Xp+48; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eI6Xp+48" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9DBBEC4CEF1; Mon, 1 Dec 2025 13:38:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764596284; bh=Z70NDaPe+lKHzewSCi3t9HKBO5LDjbDqeteLg/sp2yo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eI6Xp+48ZBt4GbOOX4exFrzy6/4TEDRo9d0tLIkHeoBHFr9EohnhCQWTOLfX8D2+j K/RAvkRkTrOtQFqnQO2itCEX2/Ile1ssk4YAOOIx/Yof5vxzenyv0dmvglyseu8nC2 hgaD0W5J38EZz/BQpcvYdpTCOucQdsOpyTzucFqgwL6QfyD7KfpeApw+QG+r4ZArMl n3HaL2UyUSFcZ0x9xqDiAT6a4zNLtlgnnwZ3cgVe3mJxIsFufSHE5LxBlO04ZIg63E QtIGT8c6aHBGyfQucmDha3WNZ8J84YXg8Hq++HwHCPSnmOABefp1UpZjeZnFHUPmw/ FJeXcvwG6W2Zw== Received: from johan by xi.lan with local (Exim 4.98.2) (envelope-from ) id 1vQ46S-000000003MT-3loZ; Mon, 01 Dec 2025 14:38:09 +0100 Date: Mon, 1 Dec 2025 14:38:08 +0100 From: Johan Hovold To: "Ji-Ze Hong (Peter Hong)" Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, tom_tsai@fintek.com.tw, yu_chen@fintek.com.tw Subject: Re: [PATCH V2 1/1] USB: serial: f81232: fix incomplete serial port generation Message-ID: References: <20251128085244.14044-1-peter_hong@fintek.com.tw> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251128085244.14044-1-peter_hong@fintek.com.tw> 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) > --- > 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. Johan