Re: Help: undesired 10 seconds delay in creating USB devices

[Kay Sievers]

On Thu, Oct 23, 2008 at 21:36, Greg KH <greg@xxxxxxxxx> wrote:
> On Thu, Oct 23, 2008 at 04:30:34PM -0300, Gu, Mingkun wrote:
>> > -----Original Message-----
>> > From: Greg KH [mailto:greg@xxxxxxxxx]
>> > Sent: Thursday, October 23, 2008 1:14 PM
>> > To: Gu, Mingkun
>> > Cc: linux-kernel@xxxxxxxxxxxxxxx
>> > Subject: Re: Help: undesired 10 seconds delay in creating USB devices
>> >
>> > On Thu, Oct 23, 2008 at 01:11:00PM -0300, Gu, Mingkun wrote:
>> >
>> > Please stop sending email in HTML format, the mailing lists reject it.
>> >
>> > > [MKGU>] My device driver name is "usbled". Our USB device has
>> > > VendorID=11b4. After I unplugged the USB cable connecting to this
>> device
>> > > and kept the device driver "usbled" remaining loaded, I plugged in
>> the
>> > > USB cable back to the system again. I could see the device
>> information
>> > > retrieved from /proc/bus/usb/devices immediately but the device name
>> > > /dev/usbled0 was seen after near 10 seconds.
>> >
>> > That sounds like a udev script issue, not a kernel issue, correct?
>> >
>>
>> [MKGU>] Yes. It seems related to udev.
>>
>> > > > If you run 'udevadm monitor', does it show a 10 second delay?
>> > >
>> > > [MKGU>] I don't have the program 'udevadm' on my system.
>> >
>> > Do you have the program 'udevmonitor'?  I suggest trying that.
>> >
>>
>> [MKGU>] Yes, I ran "udevmonitor" and captured the following messages:
>> UEVENT[1224775488.005799] remove   /class/usb/usbled0 (usb)
>> UEVENT[1224775488.007901] remove   /class/usb (class)
>> UEVENT[1224775488.011992] remove
>> /devices/pci0000:00/0000:00:1d.1/usb3/3-1/3-1:1.0 (usb)
>> UEVENT[1224775488.019706] remove
>> /devices/pci0000:00/0000:00:1d.1/usb3/3-1 (usb)
>> UEVENT[1224775496.176576] add
>> /devices/pci0000:00/0000:00:1d.1/usb3/3-1 (usb)
>> UEVENT[1224775496.181732] add
>> /devices/pci0000:00/0000:00:1d.1/usb3/3-1/3-1:1.0 (usb)
>> UEVENT[1224775496.186031] add      /class/usb/usbled0 (usb)
>
> Then I suggest filing a bug with your distro to get this looked at, as
> they are responsible for the udev scripts here, nothing wrong with your
> kernel :)

You don't have UDEV[...] events here? The interesting output of
udevmonitor would the timing difference between the kernel events and
the udev events, but you completely miss the udev ones.

What version of udev, and which distro is that?

Kay
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