Re: [Bugme-new] [Bug 11741] New: Webcam: Logitech QuickCam Communicate won't work with 2.6.27

Hans de Goede <j.w.r.degoede@xxxxxx> · Sat, 11 Oct 2008 20:14:56 +0200

Andrew Morton wrote:

(switched to email.  Please respond via emailed reply-to-all, not via the
bugzilla web interface).

On Sat, 11 Oct 2008 10:13:36 -0700 (PDT) bugme-daemon@xxxxxxxxxxxxxxxxxxx wrote:

http://bugzilla.kernel.org/show_bug.cgi?id=11741

           Summary: Webcam: Logitech QuickCam Communicate won't work with
                    2.6.27
           Product: Drivers
           Version: 2.5
     KernelVersion: 2.6.27
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: high
          Priority: P1
         Component: Other
        AssignedTo: drivers_other@xxxxxxxxxxxxxxxxxxxx
        ReportedBy: michael.letzgus@xxxxxxxxxxxxxxxx

Latest working kernel version: 2.6.26.2 + additional GSPCA
Earliest failing kernel version: 2.6.27 (with internal GSPCA)

It's a regression.

Nack, GSPCAv1 was never part of the official kernel, so the cam did not work 

*at all* with the previous official kernel, this is not a regression. Also see 

below about features which gscpa as in kernel misses compared to the old one, 

where the missing of this features actually is a feature.

Distribution: Debian lenny
Hardware Environment: AMD64, Core2Duo

Problem Description:

Camera does not work!

Is it due to DVB or to USB?

??

Its a USB cam.

Trying "camstream":
 VDLinux::run() VIDIOCMCAPTURE failed (Invalid argument)
 run(): VIDIOCSYNC(1) failed (Invalid argument)

That is because camstream is a v4l1 application and the new gspca is a v4l2 

driver. Besides that camstream does not support the JPEG image format produced 

by zc3xxx cam's such as yours. gspcav1 (the out of tree version) used to do 

JPEG decompression in kernelspace and happily offer RGB format data to 

applications, even though the cam does not, doing in kernel format conversion 

and esp. decompression is completely unacceptable, this clearly belongs in 

userspace.

I've written a userspace library which handles the format conversion in 

userspace, and which can be used as a libc library wrapper to transparently do 

format conversion for apps which need this. As an added bonus it can also 

emulate the v4l1 API on top of v4l2 devices, see:

http://hansdegoede.livejournal.com/3636.html
Download the latest version here:
http://people.atrpms.net/~hdegoede/libv4l-0.5.0.tar.gz

And see the README for installation instructions, then LD_PRELOAD v4l1compat.so 

and camstream should work fine. Note that work is underway to write patches for 

all FOSS v4l using apps to use libv4l directly so that LD_PRELOAD wont be 

necessary, see:

http://linuxtv.org/v4lwiki/index.php/Libv4l_Progress

Also note that the Ubuntu devs are aware they need to patch all their apps to 

use libv4l to work seamlessly with cams supported by the new gspca when moving 

to 2.6.27. I'm very certain they know this as I personally told their 

kerneldevs this at the Plumbers conference.

Skype:
 No error message but colorful noise instead of input signal

I don't know what skype does at it is closed source, I do know many people have 

successfully used it with the new gspca in combination with LD_PRELOAD 

v4l1compat.so

Regards,

Hans

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