Quoting Joe Burks <joe-v4l@xxxxxxxxxxx>: > I've been trying to use usbvideo for the webcam driver I'm writing, but have > come up with a problem I'm hoping someone here will have an idea how to fix: > > The reverse engineering of the camera is not complete enough to determine if > the camera supports isochronous usb transfers for video streaming. You can use any transfer method, bulk transfers being the obvious candidate. I haven't incorporated the bulk transfer data pump into the usbvideo code because I don't have any device that would need it. > I expected to just send frame requests one after another, however > usbvideo_startDataPump is pretty particular about what kind of data it > expects. It works for Isoc transfers. What you need to do is to add another small procedure to usbvideo, call it usbvideo_startBulkDataPump() and initiate the bulk processing there. You probably will want to either split existing Isoc callback or write another for bulk transfers because Isoc transfers are segmented into packets, and bulk ones are not. But you will want to dump the data into the same ring queue, no changes there. > It works pretty well for the ibmcam stuff, but I noticed that the > ultracam driver (the only other driver in my 2.4.17 tree I noticed using > usbvideo) doesn't seem to support the streaming video at all (I'm guessing > because the driver authors weren't sure how to stream the video, or knew that > you couldn't stream video with isoc transfers). The ultracam driver is maintained by another person, I don't really know how it works and what it does because it requires quite rare hardware (camera with UltraPort and an IBM notebook to match). There is another driver, webcamgo, which apparently uses usbvideo. > usbvideo so that it supports serial frame grabbing, but I don't have an ibm > camera to make sure I don't break the existing driver using usbvideo. Send your patches to linux-usb-devel list and I will test. I have plenty of IBM cameras. Thanks, Dmitri -- The people who created MIME not only should be convicted, they should be shot on the spot. (Linus Torvalds)
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