* Németh Márton <nm127@xxxxxxxxxxx> [11-10-18 22:14]: > Hi Lars, > > Lars Noschinski wrote: > > I'm using a webcam (Philipps SPC500NC) which identifies itself as > > > > 093a:2603 Pixart Imaging, Inc. PAC7312 Camera > > > > and is sort-of supported by the gspca_pac7311 module. "sort-of" because > > the image alternates quickly between having a red tint or a green tint > > (using the gspac driver from kernel 3.0.0, but this problem is present > > since at least 2.6.31). > > The most important source code for your webcam is drivers/media/video/gspca/pac7311.c . > You can see it online at http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=drivers/media/video/gspca/pac7311.c . > > > If I remove and re-plugin the camera a few times (on average around 3 > > times), the colors are stable. > > When you plug and remove the webcam and the colors are wrong, do you get any > message in the "dmesg"? I get the same messages; sometimes the order of the messages output by uhci_hcd ehci_hcd differs, but this seems to be unrelated to working/not working. > Once the colors are stable and you unplug and replug the webcam, what happens then? > Is there again around 3 times when the webcam is not working properly? I now did a longer series of unplug&replug: Over the time, status "stable colors" seemed to get more probable. After a while, it only falls back to alternating colors, when I unplug it for a longer time (say 10 seconds). Might be a hardware problem? > > Then a second issue becomes apparent: > > There is almost no saturation in the image. Toying around with Contrast, > > Gamma, Exposure or Gain does not help. What _does_ help is the Vflip > > switch: If I enable it, the image is flipped vertically (as expected), > > but also the color become a lot better. > > Is there any difference when you use the "Mirror" control? What about the > combination of the "Vflip" and "Mirror" controls? "Vflip" and ("Vflip" and "Mirror") change color; "Mirror" alone does not. > What about the "Auto Gain" setting? Is it enabled or disabled in your case? Auto Gain is enabled; but colors also change if it is disabled > > > Is there something I can do to debug/fix this problem? > > You can try testing the webcam with different resolutions. The webcam > supports 160x120, 320x240 and 640x480 resolutions based on the source code. > You can try the different resolutions for example with "cheese" > ( http://projects.gnome.org/cheese/ ) or any of your favorite V4L2 program. This does not seem to make a difference; except that 160x120 is listed, but does not seem to be available. guvcview tells me: Checking video mode 640x480@32bpp : OK setting new resolution (320 x 240) checking format: 859981650 Checking video mode 320x240@32bpp : OK setting new resolution (160 x 120) checking format: 859981650 Checking video mode 160x120@32bpp : OK ioctl (-1067952623) retried 4 times - giving up: Die Ressource ist zur Zeit nicht verfügbar) VIDIOC_DQBUF - Unable to dequeue buffer : Die Ressource ist zur Zeit nicht verfügbar Error grabbing image (the last message is then repeated, till i change the resolution) [Also, since I switched to 160x120, cheese crashes with a segfault, without giving me the possibility to switch back and I cannot find the config file.] > You can load the usbmon kernel module and use Wireshark to log the USB communication > between your computer and the webcam starting with plug-in. You can compare > the communication when the webcam starts to work correctly with the one when > the webcam doesn't work as expected. I'll try to do this later this week. Greetings, Lars Noschinski -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
