Hi, It is probably best to resend this mail to linux-usb <linux-usb@xxxxxxxxxxxxxxx> since this is more of a usb problem then a v4l2 problem, and all the usb experts are subscribed to that list. Regards, Hans On 07-04-16 17:36, Matthew Giassa wrote:
Good day, I maintain an SDK for USB2.0 and USB3.0 U3V machine vision cameras, and several of my customers have reported severe issues since upgrading from kernel 3.19.0-51 (Ubuntu 14.04.3 LTS) to kernel 4.2.0-34 (Ubuntu 14.04.4 LTS). I've received helpful advice from members of the libusb and linux-usb mailing list and development groups on how to generate useful logs to help diagnose the issue, and have filed a bug to track this issue at: https://bugzilla.kernel.org/show_bug.cgi?id=115961 It seems that with kernels newer than the 3.19 series (I've tested on 4.2.0-34, and just repeated the tests on the latest 4.5.0 release), the cameras lock up, and cannot stream image data to the user application. I am able to resolve the issue on 4.2.0-34 by disabling USB power management by adding "usbcore.autosuspend=-1". On the 4.5 kernel, this "trick" doesn't work at all, and I have no way to get the cameras to stream data. I can do simple USB control requests to query things like register values and serial numbers, but that's it. Asynchronous bulk transfers never succeed. Special Cases: * The issue does not occur when using USB2.0 cameras on a USB2.0 port, regardless of the kernel in use. * The issues occur only on Intel 8 Series and Intel 9 Series USB3.0 host controllers with 4.x kernels. * Intel 10 Series host controllers have not yet been tested. * The issues never occur on Fresco or Renesas host controllers, regardless of the kernel in use. * From visual inspection of lsusb output, the issue only appears to happen when the U1 and U2 options are available to the device. I would like to request assistance with diagnosing and resolving the issue, as it requires our customers to either not use Intel host controllers, or sticking to older kernel releases. Thank you for your time and assistance. ============================================================ Matthew Giassa, MASc, BASc, EIT Security and Embedded Systems Specialist linkedin: https://ca.linkedin.com/in/giassa e-mail: matthew@xxxxxxxxxx website: www.giassa.net -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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