Hi, On Monday 14 February 2011 01:25:49 xinglp wrote: > On 2011/2/13 Hans Verkuil wrote: > On Sunday, February 13, 2011 13:33:27 xinglp wrote: > > 2011/2/13 Hans Verkuil <hverkuil@xxxxxxxxx>: > > > On Sunday, February 13, 2011 09:18:41 xinglp wrote: > > >> It seems like that epoll_wait() do not return as soon as possible when > > >> one frame be captured, it only returns when 4(set by > > >> ioctl(..VIDIOC_REQBUFS..).) frames be captured. > > >> And v4l2_buffer::sequence indecates one lost per 4 frames. > > > > > > What hardware/driver are you using? > > > > I' using uvcvideo. I've tried two cheap usbcam at two PC. > > > > lsusb > > Bus 002 Device 002: ID 1871:01f0 Aveo Technology Corp. > > > > lsmod > > Module Size Used by > > uvcvideo 54924 - > > videodev 65184 - > > > > DG45ID mainboard and a hp2530p notebook. > > A quick follow-up: I could reproduce this with uvc. It works fine with vivi > and gspca, so this seems to be a uvc bug. > > Please post this bug report to the linux-media mailinglist with a CC to > Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> who is the uvc > maintainer. I'm not sure if the problem lies in uvcvideo or in the epoll implementation, but I'm working on using videobuf2 in uvcvideo, and that will fix the issue. > > >> The source in attachment can reproducte it, run it with option --epoll > > >> to make it use epoll. > > >> > > >> The attachment is a modified version of the follow URL. > > >> http://v4l2spec.bytesex.org/v4l2spec/capture.c > > > > > > I can't reproduce this with the vivi driver. It's much more likely to > > > be a driver issue. > > > > On my machine, vivi even not work with epoll(). only capture one frame > > and stop.(epoll_wait() never return again.) > > > > > BTW, it's much better to mail the linux-media mailinglist. Also note > > > that Bill is no longer involved in V4L. > > > > I can't subscribe any kernel maillist successfully. -- Regards, Laurent Pinchart -- 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
