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 9ED751DD9AC; Thu, 16 Jan 2025 15:03:02 +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=1737039782; cv=none; b=WC2bTctsG5iCl9UftyGBpf7C75axk6aGAbriQ0112pbulX0AxBB+4L6Mk6p/I93tbjPXd8TNNEpuacasyJP1G5NEgIVU5gVGcbd2Eg4RsxGfkUFG970JcbMeT39/L6mCjeVYT7R534bn0SqRbNSVS7w6WrN7u2eh2kP3Zr5osCM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737039782; c=relaxed/simple; bh=RSivkfPn3uPsOvEF1NGjwlpMFMXrKr1RrLcNfU4XDIM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OIlsFs93C5Qea6kySjk0Yheo8CDczs1OpRaD919gKHZUFm6T2wEAca977mkM2cuphJsq7RjLK0IvR7K2hExMrzHBVYEFgXml2U7lA0tcON68Qh+5Ratzlb4rhslfaENReKCD3ih+elmwKdROQJlWC+aW/KeEO5QMr/42ZTsKO4k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K/mssTjD; 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="K/mssTjD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E9C0C4CEE6; Thu, 16 Jan 2025 15:03:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737039782; bh=RSivkfPn3uPsOvEF1NGjwlpMFMXrKr1RrLcNfU4XDIM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=K/mssTjDHclAPCR2cRjzr7m/cD7WuGCkxMH5nVPvOekIzZxnPaUoDvxX6dwL9dLfo kr6PqiDcxtJI5u5HIl2h5qrZfINSwDNMDi0wuKcEH8Pg7jO3ishuS+t2Gn8vuiVTfW ozBASlrTcLrG8uOeaLk6hDAj+pqPWKmVRxAJ+HkSuyrIlU+ztGZhI5xTwdF7Hc29FS HNpq0Y6H4K1+/env5ZzHadf31Lto1Xss1f37AVDjTiwYykvIB0b0cEHC5dggTWspCj nxDHJxmiKoEUQQAkZr7Qqh3XFM5T7G3mEilCYivT554d4tt7gLd5mpOAS19z3YR4nr WfIuN1HvkBGiA== Received: from johan by xi.lan with local (Exim 4.97.1) (envelope-from ) id 1tYROl-000000001zW-0ua8; Thu, 16 Jan 2025 16:03:07 +0100 Date: Thu, 16 Jan 2025 16:03:07 +0100 From: Johan Hovold To: Martin Blumenstingl Cc: Corentin Labbe , gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, david@ixit.cz Subject: Re: [PATCH 1/1 v7] usb: serial: add support for CH348 Message-ID: References: <20240507131522.3546113-1-clabbe@baylibre.com> <20240507131522.3546113-2-clabbe@baylibre.com> 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: On Tue, Jan 14, 2025 at 10:40:56PM +0100, Martin Blumenstingl wrote: > > Not sure what Corentin has been preparing, but yeah, you need some kind > > of deferred mechanism to make write() non-blocking and hold off sending > > more data to the device until you're sure there's room in its buffers. I > > guess a workqueue should do fine. > We're currently testing an updated driver based on a workqueue > (work_struct) and it's working fine. > The issue that Corentin reported is unrelated to the workqueue part. > At this point we're thinking it may be a regression in linux-next, but > we're running more tests to verify this. You don't need to test the driver against linux-next, rc7 should do just fine for a driver like this. Let's see what the new implementation looks like. Perhaps you don't even need to use a workqueue (e.g. send off the single URB from the completion callback when you get a notification that the transmitter has emptied). Johan