On Fri, 13.06.08 18:26, Takashi Iwai (tiwai@suse.de) wrote:
Wait, wait. Please don't mix up. The above doesn't imply anything about the further implementation of usb-audio driver. What I suggested is, instead of hiding two pointers (hw_ptr and curr_ptr) and creating a complex API, simply expose them.
Now, regarding the usb-driver. Honestly, I don't understand what you want to do with an extra URB.
As now, usb-audio driver handles as curr_ptr == hw_ptr. But, in reality, curr_ptr = hw_ptr - samples_in_urbs. So, in the case of USB-audio, hw_ptr is ahead of curr_ptr. (And the granularity is samples_in_urbs).
BTW: what's the relation between periods and URBs on usb-audio right now? I mean, the URBs should be exposed as periods to userspace, right? But they are not right now, are they? I mean, I can set all kinds of strange period settings for my USB device and I am pretty sure that this is not reflected in the URB size, or am I wrong?
Lennart