From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68BA2C433F5 for ; Fri, 28 Jan 2022 11:23:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230302AbiA1LXj (ORCPT ); Fri, 28 Jan 2022 06:23:39 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:35418 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230042AbiA1LXj (ORCPT ); Fri, 28 Jan 2022 06:23:39 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A8A6DB8253F; Fri, 28 Jan 2022 11:23:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D57C4C340E0; Fri, 28 Jan 2022 11:23:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643369016; bh=mChaVS62VRMHxG9WuKRILek2xzuVDIFdda4zjzrKGug=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lfWbvoHuVgVw8qF5T7BF7/vfDR862M47wwOioeKxyj0dNh+oKPkWjZi103G8axr4N E0oMhWORR0EynMfo+F4e3sQHT6qdO37gLlFT3DcI9NAKVIXnDlgHlH/rEI6uxPkdca hAwpASLOJ8ujfLF4xzzbsH2KSNYC+I9EyK4rl9DE= Date: Fri, 28 Jan 2022 12:23:33 +0100 From: Greg KH To: Oleksij Rempel Cc: Oliver Neukum , netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, Jakub Kicinski , "David S. Miller" Subject: Re: [PATCH net-next v1 1/1] usbnet: add devlink support Message-ID: References: <20220127110742.922752-1-o.rempel@pengutronix.de> <20220127123152.GF9150@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Fri, Jan 28, 2022 at 12:12:38PM +0100, Oleksij Rempel wrote: > On Thu, Jan 27, 2022 at 02:22:49PM +0100, Greg KH wrote: > > On Thu, Jan 27, 2022 at 01:31:52PM +0100, Oleksij Rempel wrote: > > > On Thu, Jan 27, 2022 at 12:13:53PM +0100, Greg KH wrote: > > > > On Thu, Jan 27, 2022 at 12:07:42PM +0100, Oleksij Rempel wrote: > > > > > The weakest link of usbnet devices is the USB cable. > > > > > > > > The weakest link of any USB device is the cable, why is this somehow > > > > special to usbnet devices? > > > > > > > > > Currently there is > > > > > no way to automatically detect cable related issues except of analyzing > > > > > kernel log, which would differ depending on the USB host controller. > > > > > > > > > > The Ethernet packet counter could potentially show evidence of some USB > > > > > related issues, but can be Ethernet related problem as well. > > > > > > > > > > To provide generic way to detect USB issues or HW issues on different > > > > > levels we need to make use of devlink. > > > > > > > > Please make this generic to all USB devices, usbnet is not special here > > > > at all. > > > > > > Ok. I'll need some help. What is the best place to attach devlink > > > registration in the USB subsystem and the places to attach health > > > reporters? > > > > You tell us, you are the one that thinks this needs to be reported to > > userspace. What is only being reported in kernel logs that userspace > > somehow needs to see? And what will userspace do with that information? > > The user space should get an event in case there is a problem with the > USB transfers, i.e. the URB status is != 0. That's pretty brave, lots of things can have a urb status of != 0 in semi-normal operation, have you tried this? > The use space then can decide if the USB device needs to be reset, power > cycled and so on. > > What about calling a to-be-written devlink function that reports the USB > status if the URB status is not 0: > > diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c > index d0f45600b669..a90134854f32 100644 > --- a/drivers/usb/core/hcd.c > +++ b/drivers/usb/core/hcd.c > @@ -1648,6 +1648,8 @@ static void __usb_hcd_giveback_urb(struct urb *urb) > usb_unanchor_urb(urb); > if (likely(status == 0)) > usb_led_activity(USB_LED_EVENT_HOST); > + else > + devlink_report_usb_status(urb, status); Try it and do lots of transfers, device additions and removals and other things and let us know what it reports. thanks, greg k-h