On Tue, 13 Sep 2005, Leslie Katz wrote:
> > It should be /sys/module/usbcore/parameters/usbfs_snoop (this may
> > vary
> > depending on which version of the kernel you use). And maybe "1"
> > would be
> > better than "y"; I'm not sure. But basically, yes.
> >
> > At any rate, when a subsystem has been compiled into the kernel
> > instead of
> > built as a module, you can set parameters for it on the boot command
> > line.
> > For instance, you could interactively edit the grub boot parameters
> > when
> > you start up, and add
> >
> > usbcore.usbfs_snoop=1
> >
> > to the end of the line. That would have the desired effect.
Actually, it turns out that either way will work. Of course, if you put
the parameter on the boot command then the change will take effect as soon
as you boot.
> Here is a summary of what I've tried to do in accordance with your
> request.
>
> I booted up with the camera plugged in.
>
> Immediately after booting up, I looked at the dmesg output. It may be
> worth reporting the following lines:
>
> "usb 3-2: new full speed USB device using uhci_hcd and address 2
> usb 3-2: device not accepting address 2, error -71
> usb 3-2: new full speed USB device using uhci_hcd and address 3
> usb 3-2: device not accepting address 3, error -71
> usb 3-2: new full speed USB device using uhci_hcd and address 4
> usb 3-2: device descriptor read/64, error -71
> usb 3-2: device descriptor read/64, error -71
> usb 3-2: new full speed USB device using uhci_hcd and address 5
> usb 3-2: device descriptor read/64, error -71
> usb 3-2: device descriptor read/64, error -71"
>
> After bootup, I asked gphoto2 to auto-detect the camera. It didn't. I
No wonder, since the camera was never initialized properly.
> unplugged the camera and plugged it back in. gphoto2 then detected the
> camera correctly, but would not download any images.
Odd that it should initialize after booting but not while booting...
> I checked dmesg after that and found one new line added to the end. It
> said, "usb 3-2: new full speed USB device using uhci_hcd and address
> 6".
>
> I edited /boot/grub/grub.conf. What I think were the relevant lines
> said beforehand,
>
> "title Fedora Core (2.6.11-1.35_FC3)
> root (hd1,0)
> kernel /vmlinuz-2.6.11-1.35_FC3 ro root=LABEL=/ rhgb quiet
> acpi=off"
>
> I added a space and then "usbcore.usbfs_snoop=1" after "acpi=off".
>
> I rebooted with the camera still plugged in.
>
> I ran dmesg. Again there were a series of lines about errors re usb
> 3-2, but they differed from the lines the first time. I then followed
> the steps I'd followed before amending grub.conf: failed auto-detect,
> unplug camera, plug back in, gphoto2 auto-detects now, but won't
> download, I look at dmesg, nothing more than the line, "usb 3-2: new
> full speed USB device using uhci_hcd and address 6", which I take to be
> the result of having unplugged the camera and plugged it back in. There
> was no new information as a result of my amendment of grub.conf.
>
> I next amended grub.conf, sustituting a "y" for the "1" I'd earlier
> tried. I rebooted and went through all of the steps above, with exactly
> the same result as before. Only one line was added to dmesg, the one
> that acknowledged the replugging of the camera.
>
> It's plain that I'm not doing what needs to be done to get usbfs_snoop
> working. Having tried setting the thing by using "1" and then "y", I've
> got no additional information at all.
>
> Can it be that I haven't inserted the information at the appropriate
> point in my grub.conf file? Apart from raising that, I don't know what
> else to think.
As far as I can see, you're doing everything correctly. For now, don't
worry about what happens when the camera is plugged in a boot time; just
concentrate on the problems when the camera is plugged in later.
You can easily test whether your "usbfs_snoop=y" has worked by running
"lsusb -v". That should cause a lot of snoop messages to show up in the
dmesg log, even if you don't have any USB devices plugged in. If you're
running at a text console (not an X window) and as root you do
echo 9 >/proc/sys/kernel/printk
then you will see those snoop messages interspersed with the output from
lsusb. Or you could run "lsusb -v >/dev/null", in which case you'd see
nothing but the snoop messages.
Give me some time to download the libgphoto2 source code and look through
it. I'll get back to you about it.
Alan Stern
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