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Date:   Thu, 25 Mar 2021 14:59:03 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     liulongfang <liulongfang@huawei.com>
Cc:     mathias.nyman@intel.com, stern@rowland.harvard.edu,
        linux-usb@vger.kernel.org, yisen.zhuang@huawei.com,
        tanxiaofei@huawei.com, liudongdong3@huawei.com,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] USB:XHCI:Adjust the log level of hub
Message-ID: <YFyXJ1Zq5yP7vRWn@kroah.com>
References: <1616666652-37920-1-git-send-email-liulongfang@huawei.com>
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 <d2fc6d09-c8e7-436f-3e0d-b2cfa9c75b9f@huawei.com>
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On Thu, Mar 25, 2021 at 09:33:53PM +0800, liulongfang wrote:
> On 2021/3/25 18:31, Greg KH wrote:
> > On Thu, Mar 25, 2021 at 06:04:12PM +0800, Longfang Liu wrote:
> >> When the number of ports of the hub is not between 1 and Maxports,
> >> it will only exit the registration of the hub on the current controller,
> >> but it will not affect the function of the controller itself. Its other
> >> hubs can operate normally, so the log level here can be changed from
> >> error to information.
> >>
> >> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
> >> ---
> >>  drivers/usb/core/hub.c | 10 ++++------
> >>  1 file changed, 4 insertions(+), 6 deletions(-)
> >>
> >> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> >> index b1e14be..70294ad 100644
> >> --- a/drivers/usb/core/hub.c
> >> +++ b/drivers/usb/core/hub.c
> >> @@ -1409,13 +1409,11 @@ static int hub_configure(struct usb_hub *hub,
> >>  		maxchild = min_t(unsigned, maxchild, USB_SS_MAXPORTS);
> >>  
> >>  	if (hub->descriptor->bNbrPorts > maxchild) {
> >> -		message = "hub has too many ports!";
> >> -		ret = -ENODEV;
> >> -		goto fail;
> >> +		dev_info(hub_dev, "hub has too many ports!\n");
> > 
> > Is this an error?  If so, report it as such, not as "information".
> > 
> >> +		return -ENODEV;
> >>  	} else if (hub->descriptor->bNbrPorts == 0) {
> >> -		message = "hub doesn't have any ports!";
> >> -		ret = -ENODEV;
> >> -		goto fail;
> >> +		dev_info(hub_dev, "hub doesn't have any ports!\n");
> > 
> > Same here.
> > 
> > What problem are you trying to solve here?
> > 
> > What hub do you have that has no ports, or too many, that you think
> > should still be able to work properly?
> > 
> > thanks,
> > 
> > greg k-h
> > .
> On our test platform, the xhci usb3 hub has no port.

Sounds like a broken device, why not fix that?

> when initializing the usb3 hub, an error will be reported
> because the port is 0, but in fact it will not affect
> the use of usb2, and the usb2 hub is working normally.

But you can not have a USB3 hub with no ports, isn't that against
against the USB spec?  How does this device pass the USB-IF
certification?

> thanks, therefore, in order to reduce the severity of the log,
> we hope to lower the level of this log.

You did not reduce the severity at all, everyone can still see it.

Please try fixing your hardware :)

thanks,

greg k-h