Hi, I am trying to implement UVC bulk transfer for my webcam. The following what I am doing
1) After I get VS_COMMIT_CONTROL 2) I am waking up my streaming thread, which transmit the data to the FIFO 3) I can see the data coming to the host through USB analyzer. 4) But followed that I am not getting ACK from the host machine. uvcvideo module gives ERROR (-75). I am attaching log file generated by host side machine. After this error, the host sends RESET signal to the device which re-enumerates the device. My payloadTransferSize is 2048 bytes. I have already sent my descriptor set about my camera. Is there anything I am doing wrong or missing something. Can you guys please help on this ? Thanks & Regards, Ramesh. On Wed, Nov 11, 2009 at 5:13 PM, Ramesh Rajagopal <shm...@gmail.com> wrote: > > Hi Laurent, > Thank you for the reply. The webcam is linux based and I am using the > UVC gadget driver of linux kernel 2.6.10. > In this kernel I don't see any example doing UVC bulk transfer. It is > working perfectly with ISOC. > Can you please let me know, if there is any example code that does UVC bulk > transfer ? I couldn't find it any. > > The uvc specification is not clear enough to distinguish ISOC and BULK > transfer atleast from my understanding. > > While doing ISOC transfer, we have an alternate Interface Setting, when we > get a SET_INTERFACE we start transferring the UVC header first alone to > start > the transfer. There after each IN token from host will carry the frames if > any, otherwise header alone goes. > > In case of BULK, with alternate settings, the host machine hangs. > SET_INTERFACE (alternateSetting set 1), Why is it like that? > > So I removed alternate settings and till enumeration it is proper. Then > After I get VS_PROBE_COMMIT from the host, I start transferring exactly same > like ISOC, but > I don't see any video on the host and no more proceedings from here. The > data is not going from the FIFO, hence I am not getting any more TX > interrupt from my device. > > I am attaching my devices descriptor as well as host side logs. Please find > the attachment. Please let me know, is there any link talk about BULK > transfer or example. > > > Thanks & Regards, > Ramesh. > > > > > On Wed, Nov 11, 2009 at 5:13 AM, Laurent Pinchart < > laurent.pinch...@ideasonboard.com> wrote: > >> Hi Ramesh, >> >> On Tuesday 10 November 2009 17:03:50 Ramesh Rajagopal wrote: >> > Hi, >> > I am trying to implement UVC bulk tranfer for my webcam. I am getting >> some >> > difficulties. >> > If anybody has already tried, Can you please send me the enumeration >> > details.? >> >> Are you developing a webcam ? Is it Linux-based ? If so, are you using the >> UVC >> gadget driver I've posted to the linux-usb mailing list some time ago ? >> >> You will find sample USB descriptors for a bulk device attached to this e- >> mail. >> >> > Does this same as ISOC transfer or is it different, If so, Please give >> me >> > those details. >> >> What about reading the UVC spec ? >> >> -- >> Regards, >> >> Laurent Pinchart >> > >
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