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 46AB62701BD; Sat, 6 Sep 2025 13:13:14 +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=1757164395; cv=none; b=WOIDYslcxE/FlEz3MHjgw6UVwiRQdSM9HfnXgN9vlfzg7BJ3wBt/GmKkHVxhgCrc+As9R6g/XxY/BJrLWNjtlIGxHdgNL9u2UNDE8lI/sHJ6vdNq4A+HflhwSptGKFiokynufZ7s8WYIWRUYNZA2yVkpB3ki6Hr+6vuMrs7siEI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757164395; c=relaxed/simple; bh=DEcm+7zFwIRgV12nXW0jApJsCHVEQfgXXb/sxTjUq7k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GJmPEG2D2Lp25UnjjxGmBp3NO4sFJym9WT5+6mxq5ZSvPGdUM+xFYDhSjWgV+LSdNv920cCSHzdyWO5ETD2r5dBvePfE++hjjorrslq29iz8+BWllHkI6FMqHca5Rr3CkdqlpcFojdy7FiVm1sOW1deXAeTidkPizVkrKzdW6Rg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BbOAxFw2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BbOAxFw2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49DB1C4CEE7; Sat, 6 Sep 2025 13:13:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1757164394; bh=DEcm+7zFwIRgV12nXW0jApJsCHVEQfgXXb/sxTjUq7k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BbOAxFw2tbcbYCOyVHbRuq0PqvFy2v9XxXOrzIJ/Jqx9ANQCABK0VA9XiEuIIhQtp Qfmu00GhQsC7lOcb77Ppv90uqM0lXhmesbxF5UGGIwVyhHh0hgob9/WBQiKF6SyI7Q yO6dYv3S9mDZzR7MItcQsL8PkQ09PYPFDkWqs7KQ= Date: Sat, 6 Sep 2025 15:13:12 +0200 From: Greg KH To: Guan-Yu Lin Cc: mathias.nyman@intel.com, hannelotta@gmail.com, zijun.hu@oss.qualcomm.com, xu.yang_2@nxp.com, stern@rowland.harvard.edu, andriy.shevchenko@linux.intel.com, ben@decadent.org.uk, quic_wcheng@quicinc.com, krzysztof.kozlowski@linaro.org, dh10.jung@samsung.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v15 2/4] usb: offload: add apis for offload usage tracking Message-ID: <2025090650-decal-canary-8e34@gregkh> References: <20250801034004.3314737-1-guanyulin@google.com> <20250801034004.3314737-3-guanyulin@google.com> <2025081326-guileless-lego-ec59@gregkh> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, Aug 26, 2025 at 11:59:00AM +0800, Guan-Yu Lin wrote: > On Wed, Aug 13, 2025 at 10:50 PM Greg KH wrote: > > > > On Fri, Aug 01, 2025 at 03:39:31AM +0000, Guan-Yu Lin wrote: > > > + > > > +config USB_OFFLOAD > > > + bool "Enable USB offload feature" > > > > I'm confused, we already have a "USB offload feature" that went into the > > last kernel release, why do we need a separate config option for this as > > well? Shouldn't this code only get built if the drivers that need it > > select it automatically? Forcing distros to configure this isn't > > generally a good idea if at all possible. > > > > Based on the discussion in v13, a new, separate USB configuration > option is required to avoid core USB functions being enabled or > disabled via an xhci-specific option. The USB offload feature involves > a sideband entity that can access xhci resources, which, from the USB > driver's viewpoint, means USB transfers are offloaded to this other > entity. Therefore, the name "USB_OFFLOAD" was chosen to reflect this > functionality. Again, you are increasing the number of config options here, which does not make sense. Why would anyone only want a subset, and not just the whole thing? Yes, USB_OFFLOAD only works today on xhci, and that's fine, so let's just keep it that way. > > > + depends on USB > > > + depends on USB_XHCI_SIDEBAND_SUSPEND > > > > Especially because all "desktops" do not want this code selected, so > > having it in all distros feels like a waste to me. > > > > thanks, > > > > greg k-h > > For the config keywords, we could automatically select USB_OFFLOAD > once USB_XHCI_SIDEBAND_SUSPEND is selected to reduce configuration > efforts. select is a nightmare to maintain and understand. Please just reduce configuration efforts by not adding new options at all :) thanks, greg k-h