Track the USB isochronous with DMA fix that TI is working on

[BrianAdams]

https://e2e.ti.com/support/embedded/linux/f/354/t/332530#pi317016

[BrianAdams]

As of Kernel 4.1.8-ti-r18, we are still seeing issues regarding isochronous mode.

[BrianAdams]

From the Raspi community:
https://www.raspberrypi.org/forums/viewtopic.php?p=257512
raspberrypi/linux#238 (comment)
https://gist.github.com/P33M/5213278

BBB:
http://lxr.free-electrons.com/source/drivers/usb/musb/musb_am335x.c?v=4.4

Todo

• Does the BBB musb_am335x.c have a similar timing vulnerability as the Raspi driver?
• @spiderkeys is P33M's patch included in the all Raspi Kernels now?

[BrianAdams]

Follow up: It does not appear that the Genius camera uses DMA transfer. You can look at the interrupts and it is straight to the uvc driver, no DMA driver listed.

Did a side by side, the 30.0.1 release does not have a problem with the Genius camera. The dev releases with Kernel 4.4.19 Preempt RT (among others) most certainly do have an issue in the form of an insane number of interrupts. That said, even the 30.0.1 release has the issue with bright contrast causing the USB to freeze up.