Messages in this thread | | | Subject | Re: [PATCH] usbnet: prevent device rpm suspend in usbnet_probe function | From | Oliver Neukum <> | Date | Wed, 09 Nov 2016 12:58:55 +0100 |
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On Tue, 2016-11-08 at 13:44 -0500, Alan Stern wrote:
> These problems could very well be caused by running at SuperSpeed > (USB-3) instead of high speed (USB-2). > > Is there any way to test what happens when the device is attached to > the computer by a USB-2 cable? That would prevent it from operating at > SuperSpeed. > > The main point, however, is that the proposed patch doesn't seem to > address the true problem, which is that the device gets suspended > between probes. The patch only tries to prevent it from being > suspended during a probe -- which is already prevented by the USB core.
But why doesn't it fail during normal operation?
I suspect that its firmware requires the altsetting
/* should we change control altsetting on a NCM/MBIM function? */ if (cdc_ncm_select_altsetting(intf) == CDC_NCM_COMM_ALTSETTING_MBIM) { data_altsetting = CDC_NCM_DATA_ALTSETTING_MBIM; ret = cdc_mbim_set_ctrlalt(dev, intf, CDC_NCM_COMM_ALTSETTING_MBIM);
to be set before it accepts a suspension.
Regards Oliver
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