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From: Greg KH <gregkh@linuxfoundation.org>
To: Jupiter <jupiter.hce@gmail.com>
Cc: linux-usb <linux-usb@vger.kernel.org>
Subject: Re: Kernel 5.10 USB issues
Date: Wed, 24 Nov 2021 08:04:21 +0100	[thread overview]
Message-ID: <YZ3j9XKE0WjfkcsI@kroah.com> (raw)
In-Reply-To: <CAA=hcWTukyvM0Hz-VgW_NG7Whc3i7GLGySzJ0iGHvxo3O1f5vQ@mail.gmail.com>

On Wed, Nov 24, 2021 at 11:46:06AM +1100, Jupiter wrote:
> Hi,
> 
> I connected a USB bus between an iMX6ULZ and an 4G LTE modem, it was
> running well in kernel 4.19.75. I've just upgraded kernel to 5.10.59,
> the USB is broken, the USB drivers were disconnected / connected
> repeatedly:
> 
> [12781.730889] usb 1-1: USB disconnect, device number 84
> [12781.808317] option1 ttyUSB0: GSM modem (1-port) converter now
> disconnected from ttyUSB0

That is usually a hardware problem, the kernel can not disconnect a
device from the bus through software.

But, if 4.19 is working, can you use 'git bisect' between the two
kernels to find what caused the problem?

thanks,

greg k-h

  reply	other threads:[~2021-11-24  7:04 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-24  0:46 Kernel 5.10 USB issues Jupiter
2021-11-24  7:04 ` Greg KH [this message]
2021-11-24 10:06   ` Jupiter
2021-11-24 10:13     ` Greg KH
2021-11-25  6:03       ` Jupiter
2021-11-25  6:29         ` Greg KH
2021-11-26 16:14         ` Andy Shevchenko
2021-11-26 21:54           ` Jupiter

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