Having written a GSPCA webcam driver on a machine where everything worked perfectly, I tried it on another machine. On the second machine, it did not work so well. The decisive difference between the two machines seemed to be that the first one uses the OHCI driver for basic USB support, and the second machine uses UHCI. So I decided to test on more hardware.
At this point, I have put identical copies of the camera driver, along with identical copies of the rest of the gspca development tree, on six different machines. Three of them use OHCI, and three of them use UHCI. On the three machines which use OHCI, everything works perfectly. On the three machines which run UHCI, there are serious problems, to the extent that some of the cameras I have intended to support will not function while others do continue to work.
Various recent kernel versions are in use on the several machines tested, ranging from 2.6.27.x all the way up to 2.6.32-rc6. I have the impression that the problem is, within these boundaries, pretty much independent of the kernel version and seems to depend only upon whether the machine has got OHCI or UHCI USB chipsets on it.
I will be glad to provide further information or to run further tests if it helps to get to the bottom of the problem.
Theodore Kilgore -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
