On Tuesday 19 February 2013 23:26:19 Aman Sawrup wrote: > I believe the amount of memory reserved needs to be much higher. For > example, if sizeof(struct usb_page) is 16 bytes, then for n_frbuffers of > 128 and parm->bufsize of 131072, we need the following amount of memory > reserved: > > parm->bufsize / USB_PAGE_SIZE * n_frbuffers * sizeof(struct usb_page) > = 131072 / 4096 * 128 * 16 > = 65536
Hi, The parm->bufsize is shared for all frbuffers, so the formula should be correct. In your computation you assume that parm->bufsize gives the maximum for each frbuffer. That is not the case. That means, when you configure bufsize, you must not exceed that size as a total when setting up frames. This include all transfer types. I think there are asserts for that so you should get a panic fairly quickly. --HPS _______________________________________________ freebsd-usb@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
