Re: Odd 'unable to find transceiver' messages from USB withv3.13-3260-g03d11a0 and later

From: Josh Boyer
Date: Fri Jan 24 2014 - 15:31:38 EST


On Fri, Jan 24, 2014 at 2:08 PM, Felipe Balbi <balbi@xxxxxx> wrote:
> Hi,
>
> On Fri, Jan 24, 2014 at 08:47:07AM -0500, Josh Boyer wrote:
>> We've had a report [1] of the USB layer throwing out 'unable to find
>> transceiver' messages during boot with the 3.14 merge window kernels.
>> I've seen this on my personal machine as well and included the dmesg
>> section below. This does not happen with the 3.13 kernel.
>>
>> There are only a handful of files in git that have that error, but I
>> haven't seen anything that immediately strikes me as causing this.
>> From the dmesg output it looks like it is spit out right before a host
>> controller is registered? USB seems to be still working OK in my
>> minimal testing, so the error message is confusing.
>>
>> Thoughts?
>
> looks like it was caused because of this commit:
>
> commit 1ae5799ef63176cc75ec10e545cb65f620a82747
> Author: Valentine Barshak <valentine.barshak@xxxxxxxxxxxxxxxxxx>
> Date: Wed Dec 4 01:42:22 2013 +0400
>
> usb: hcd: Initialize USB phy if needed

Yeah, I'm pretty sure my bisect agrees with you.

> usb_get_phy_device() will pr_err() when a PHY isn't found. Looks like
> that should be pr_debug() since everything still works even without a
> PHY.

Seems correct. Who should write up the patch?

josh
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