Hi, > So here you see that calling VIDIOC_S_FMT takes 3655992 > microseconds, which is a _really_ long time. Turns out that > cafe_cam_configure() from s_fmt_cap() takes 378 jiffies. Breaking > this down, the pieces of cafe_cam_configure() and the jiffies they > take are:
I made a systemtap log of ov7670* and i2c* calls and returns inside cafe_cam_configure, with timing information: http://dev.laptop.org/~cjb/camera-time.staplog Conclusions: * We spend 3.573 seconds in cafe_cam_configure(). * Of which 3.139 seconds is in a single ov7670_write_array() call. * Which consists of 157 calls to ov7670_write(), each of which calls i2c_smbus_xfer() once. * The 157 i2c_smbus_xfer() calls take a min of 13ms and max of 25ms each, and add up to our 3.137 seconds. * We need to optimize i2c_smbus_xfer(), which is cafe_smbus_xfer(). - Chris. -- Chris Ball <[EMAIL PROTECTED]> _______________________________________________ Devel mailing list [email protected] http://lists.laptop.org/listinfo/devel
