From: Greg KH <gregkh@linuxfoundation•org>
To: Oleksij Rempel <o.rempel@pengutronix•de>
Cc: Oliver Neukum <oneukum@suse•com>,
netdev@vger•kernel.org, linux-usb@vger•kernel.org,
linux-kernel@vger•kernel.org, kernel@pengutronix•de,
Jakub Kicinski <kuba@kernel•org>,
"David S. Miller" <davem@davemloft•net>
Subject: Re: [PATCH net-next v1 1/1] usbnet: add devlink support
Date: Fri, 28 Jan 2022 12:23:33 +0100 [thread overview]
Message-ID: <YfPSNSHwTLZBv7me@kroah.com> (raw)
In-Reply-To: <YfPPpkGjL2vcv4oH@pengutronix.de>
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
next prev parent reply other threads:[~2022-01-28 11:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-27 11:07 [PATCH net-next v1 1/1] usbnet: add devlink support Oleksij Rempel
2022-01-27 11:13 ` Greg KH
2022-01-27 12:31 ` Oleksij Rempel
2022-01-27 13:22 ` Greg KH
2022-01-28 11:12 ` Oleksij Rempel
2022-01-28 11:23 ` Greg KH [this message]
2022-01-28 11:31 ` Oleksij Rempel
2022-02-02 9:14 ` Oliver Neukum
2022-01-27 17:00 ` Alan Stern
2022-01-28 11:27 ` Oleksij Rempel
2022-01-28 15:33 ` Alan Stern
2022-01-27 11:18 ` Greg KH
2022-01-27 11:19 ` Greg KH
2022-01-27 15:43 ` Andrew Lunn
2022-01-27 16:56 ` Jakub Kicinski
2022-01-27 19:59 ` kernel test robot
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