On Sat, 14 Nov 2009, Alan Stern wrote:
On Sat, 14 Nov 2009, Theodore Kilgore wrote:
Actually, I have succeeded in finding a fix for the problem at this point.
There is a sequence of commands used in the Windows driver for
setting up these cameras, which I omitted from the code in mr97310a.c. The
reason I omitted them is, some of them actually make the camera unstable
at some of the resolution settings. In particular, at 352x288 and at
176x144. The OEM driver seems to assume that the camera will stream at
320x240 and 160x120 only, even though it is capable of 352x288 and
176x144. So, as I said, I omitted the whole sequence because it seemed to
be causing nothing but trouble.
Well, so now I took a second look. There is exactly one command which sets
up the camera to stream properly if it is hooked up to a UHCI machine! I
assume, though I have no way of really knowing this without the usb
traffic analyser that I do not own, but it seems that it sets some kind of
timing. I put this one command back in (for the CIF type 1 cameras only)
and now I can report that the all of the CIF cameras will stream on all of
the machines in my house on which I have tested. This list specifically
includes the one with the VIA chipset, as well as the old Dell laptop, and
also the eeePC.
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?
But it does appear to exonerate the
uhci-hcd driver. :-)
I am sure that we are all relieved about that. Me, too.
I would highly recommend that this prospective patched version of the
driver gets included in 2.6.32 when it comes out, and not the version
of the driver which is currently found in 2.6.32-rc6.
That's up to the driver's maintainer, and it depends on the size of the
changes. It's getting rather late in the 2.6.32-rc series; big changes
at this stage are frowned upon.
I myself am a maintainer of the driver. So I assume you mean people higher
up the tree. If they want to frown, they can frown away. All I can say is,
the choice is between a version which will always work, as opposed to one
with a known bug, known to fail on some hardware. I found the problem when
I found it, and I fixed it when I could figure out how to fix it. I sent
in a patch earlier this evening. Perhaps there will be time to think it
over.
I would only add that, whenever this patch does get in my advice to any
Windows user who has one of these cameras would be to install Linux to be
able to use it. So, yes, I really do hope that the patch does not have to
wait until 2.6.33 comes out.
Cheers,
Theodore Kilgore
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