Hi!
I just want to make the case that this is quite an important issue. I
was very surprised to hear from the CIO of one of our customers that
they had the same issue. This kept them from offering Ubuntu and an
option for their Dell laptops. Like myself, these guys need to run
GoToMeeting/WebEx together with a Windows VM for business.
I understand this is probably a difficult bug and that it is difficult
to reproduce. However, this combination of WebCam + VM is required by
everybody except for a very few privileged "Linux only" developers.
> It all depends on what that devices are asking for
The Logitech C922 has a H.264 compression on the chip. The "bandwidth
calculator" (https://www.google.es/search?q=H.264+bandwidth) says it
needs 1024kBps for 1080p @ 30fps.
Not sure if this is true, and I'm not sure what the devices actually
does, though...
> Linux solved
Ok, so you have a clear idea what part of the driver causes the error,
that's a step forward.
But I can't imagine it's "real" bandwidth. USB 3.1 can handle two
full-HD screens plus a Gigabit Ethernet on the same 5GBit lanes... A few
megabit for compressed vido plus a few _kilo_ bits/s for audio...
=> Is there a way to debug these bandwidth requests for me? Maybe you
want to include bandwidth requests in the kernel logs in the future if
these issues are so wide spread?
=> Maybe you can recommend me a WebCam with tripod option that is known
to work well with Linux?
=> From what I understand I should now test with VirtualBox and KVM/QEMU
and check if the same issue appears. I will do this and let you know
about the results.
> configuration of your devices and root hubs
I've got a brand new Dell XPX 15 9370 Laptop. No other USB hubs,
devices, no change to any configuration. I chose the model because it is
supposed to be the same that Linus Torvalds uses (well, XPS 13...)
I can offer OpenVPN access to my laptop for reproducing the issues. I
also offer to buy a Logitech C922 WebCam if somebody wants to get
seriously down to this issue.
Best Regards,
Frank
---
Frank Bergmann
Dipl.-Ing., MBA
Founder ]project-open[
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