DeviceAdded question

Mon Jun 2 18:37:11 PDT 2008

While searching on this issue, I came across an Ubuntu bug report from late
Feb this year (https://bugs.launchpad.net/ubuntu/+source/hal/+bug/196811),
where someone reports pretty much the same thing as me (a logitech quickcam
not being reported as a v4l device by HAL). A bug report was also created on
fd.o (https://bugs.freedesktop.org/show_bug.cgi?id=14809), but it then was
marked as resolved & fixed even though it still doesnt work with hal-0.5.11
(I can provide a trace if required).
Any comments ?

Cheers,
Gilles
PS: I have checked out a copy of HAL with git and I m happy to try it if
someone tells me how to compile it.

On Wed, May 28, 2008 at 12:09 PM, Gilles GIGAN <gilles.gigan at gmail.com>
wrote:

> Further to my previous post, I ran udevmonitor and plugged in both webcams
> in turns.
> For the Creative NX webcam, udev sends:
> UEVENT[1211938254.674635] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2 (usb)
> UDEV  [1211938254.679570] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2 (usb)
> UEVENT[1211938254.679599] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/5-2:1.0 (usb)
> UDEV  [1211938254.693902] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/usb_endpoint/usbdev5.8_ep00
> (usb_endpoint)
> UDEV  [1211938254.776316] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/5-2:1.0 (usb)
> UEVENT[1211938254.866628] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/5-2:1.0/usb_endpoint/usbdev5.8_ep81
> (usb_endpoint)
> UEVENT[1211938254.866660] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/5-2:1.0/usb_endpoint/usbdev5.8_ep82
> (usb_endpoint)
> UEVENT[1211938254.866742] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/video4linux/video1 (video4linux)
> UDEV  [1211938254.873827] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/5-2:1.0/usb_endpoint/usbdev5.8_ep81
> (usb_endpoint)
> UDEV  [1211938254.875099] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/5-2:1.0/usb_endpoint/usbdev5.8_ep82
> (usb_endpoint)
> UDEV  [1211938254.876226] add
> /devices/pci0000:00/0000:00:1d.2/usb5/5-2/video4linux/video1 (video4linux)
> (this is the one where a video4linux HAL object is created)
>
> for the Logitech Quickcam:
> UEVENT[1211938261.097625] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1 (usb)
> UEVENT[1211938261.098128] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/usb_endpoint/usbdev1.5_ep00
> (usb_endpoint)
> UDEV  [1211938261.099268] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1 (usb)
> UDEV  [1211938261.100519] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/usb_endpoint/usbdev1.5_ep00
> (usb_endpoint)
> UEVENT[1211938261.100614] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1:1.0 (usb)
> UEVENT[1211938261.102634] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1:1.0/usb_endpoint/usbdev1.5_ep81
> (usb_endpoint)
> UEVENT[1211938261.102702] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1:1.0/usb_endpoint/usbdev1.5_ep82
> (usb_endpoint)
> UEVENT[1211938261.108634] add      /devices/virtual/video4linux/video2
> (video4linux)
> UDEV  [1211938261.110296] add      /devices/virtual/video4linux/video2
> (video4linux)
> UDEV  [1211938261.151902] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1:1.0 (usb)
> UDEV  [1211938261.153254] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1:1.0/usb_endpoint/usbdev1.5_ep81
> (usb_endpoint)
> UDEV  [1211938261.154323] add
> /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1:1.0/usb_endpoint/usbdev1.5_ep82
> (usb_endpoint)
> (for this webcam, no video4linux HAL object is created)
> In the first instance the video4linux device is a child kobject of the USB
> connection kobject. Whereas in the second case, the video4linux kobject ends
> up in /devices/virtual instead, which is the location for devices that dont
> have a real parent kobject (AFAIK). I suspect this is why the HAL
> video4linux object is not created in the second case. Can someone confirm ?
> Checking the contents of /sys/devices/virtual shows a lot of kobjects,
> including some that are properly reported by HAL. On my computer, ' lshal |
> grep "/virtual" ' shows event-input objects and ALSA objects (sequencer,
> timer), all with "linux.sysfs_path" pointing somewhere in
> /sys/devices/virtual and linux.device_file pointing to a device file in /dev
> Which brings me back to that question: why isnt the Quickcam also detected
> and reported ?
>
> cheers,
> Gilles
>
>
> On Mon, May 26, 2008 at 9:49 AM, Gilles GIGAN <gilles.gigan at gmail.com>
> wrote:
>
>> Hi all,
>> When I connect a USB webcam, org.freedesktop.Hal.Manager generates a
>> couple of DeviceAdded signals for the newly created HAL objects. One of
>> these objects usually has the 'Video4Linux' capability. These are the HAL
>> objects created when I plug in a Creative NX webcam (no microphone):
>> /org/freedesktop/Hal/devices/usb_device_41e_401c_noserial
>> /org/freedesktop/Hal/devices/usb_device_ffffffff_ffffffff_noserial
>> /org/freedesktop/Hal/devices/usb_device_41e_401c_noserial_video4linux
>> The last one in this case holds the information about V4L and is easily
>> identifiable by checking at least "info.category" and "info.capabilities".
>> However, when I connect an old Logitech Quickcam express (qc-usb driver),
>> no V4L-related object is created and I only get:.
>> /org/freedesktop/Hal/devices/usb_device_46d_840_noserial
>> /org/freedesktop/Hal/devices/usb_device_46d_840_noserial_if0
>> grep'ping syslog shows the webcam has been detected and the device file
>> created.
>>
>> Is this HAL-related or driver-related ?
>> If it is driver-related, which step (specifically which function call)
>> usually notifies HAL that a new V4L object has been added ? is it tied to
>> one of the sysfs routines ?
>> Thanks,
>> Gilles
>>
>>
>
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