Yes, I am pretty certain, that I used the same kernel for both tests. My Fedora 7 system did have its kernel upgraded at some point some weeks back from... a 2.6.19 to a 2.6.21, I belive out from memory. But this kernel-upgrade was weeks before I changed UVC drivers, I think.
Yes, I will try to find out which SVN revision made a difference. I can try it out within a day or two, I expect. But right now, I can tell you for certain, that when the UVC driver worked "for periods of multiple minuttes at a time", I wrote to mr. Xhaard asking about the luvcview output with cc to this list about this very problem. This was Friday 20. July - I see from my earlier posting, that my kernel was the current "2.6.21-1.3228.fc7". So no kernel changes was made in between. An instance of the UVC driver working "for periods of a few seconds only" is the one which I checked out from the Subversion repository last night about 12 hours ago. From my point of view, something has changed in between. I have not reconfigured the physical USB setup or anything like that, but I have been playing around with other (USB) drivers (I say this because you mention, that the problem is somehow related to timing; maybe something else than changes in the UVC source code triggered something). I will *try* to narrow this down relative to SVN revisions. Regards Morten Sabroe Mortensen -----Oprindelig meddelelse----- Fra: Laurent Pinchart [mailto:[EMAIL PROTECTED] Sendt: 13. august 2007 10:04 Til: [email protected] Cc: Morten Mortensen Emne: Re: [Linux-uvc-devel] Patch for USB problem with Logitech webcams? Hi Morten, On Monday 13 August 2007 08:25, Morten Mortensen wrote: > - I own a couple of these "fine" Logitech webcams. Something *is* changing > in the UVC-driver, because the driver I had until yesterday - a couple of > weeks old - could run the Ultra Vision and the Fusion for a period of half > a minute and up to three, four or even five minuttes. > > The latest UVC-driver runs for one to three seconds, so something has been > changed, which influences this by an order of magnitude. These scenarios > are absolutely identical for my instances of the Ultra Vision and the > Fusion. Have you used the same kernel for both tests ? Could you please try to find out which SVN revision introduced the problem ? > One wonders how Logitech circumvents the problem in their Windows drivers. They don't. The Windows USB stack seems to be slower than the Linux one, and it just doesn't trigger the problem. It's a matter of timings, and Logitech never noticed the problem. From the limited amount of knowledge I have about this bug, it seems there is a hardware problem which has been worked-around by a firmware hack in recent webcams. Both the hardware and the firmware are provided by the IC vendor, so Logitech isn't the only one to blame. > One wonders *when* manufacturers implement reflashability of their > monitors, webcams, etc. The two issues here are support and cost. They don't want to support firmware reflashing, as that would mean replacing dead webcams. And flash costs more than ROM. > Please keep up the good work. Thanks. I'll do my best :-) Regards, Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
