Hi,
On 11/15/2009 08:07 PM, Alan Stern wrote:
On Sun, 15 Nov 2009, Theodore Kilgore wrote:
That doesn't explain why the old code worked with OHCI but not UHCI.
We may never know the answer.
No, it does not explain. But I am somehow less curious about that than I
was 12 hours ago. What about you? Feel that way, too?
No, I am just as curious as before. Maybe more so, knowing it has
become even less likely that I will ever learn the answer. It's
frustrating.
One possible explanation: UHCI always carries out its periodic
transfers at the beginning of each frame. OHCI doesn't, or least, it
doesn't have to. Now there's no good reason why this should make any
difference to the cameras, but perhaps it does anyway.
FWIW, these chips are found in dirt dirt cheap camera's think 5 euros including
keychain + keychain ledlight + bateries + usb cable, and that for a still cam
camera, which can also be used in streaming mode.
We've discovered some other interestings things during driver development too,
like the camera being so cheaply made it has so little internal buffering,
it can run out of bandwidth, when a single row of the image does not compress
well.
Regards,
Hans
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