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From: Alan Stern <stern@rowland.harvard.edu>
To: Matt Corallo <oc2udbzfd@mattcorallo.com>
Cc: linux-usb@vger.kernel.org, linux-amlogic@lists.infradead.org,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Subject: Re: ODROID-C1/-C2 USB Detection only triggered by some devices
Date: Mon, 28 Jun 2021 10:24:18 -0400	[thread overview]
Message-ID: <20210628142418.GC656159@rowland.harvard.edu> (raw)
In-Reply-To: <0c62655d-738c-4d71-6b7b-fe7fa90b54e3@bluematt.me>

On Sun, Jun 27, 2021 at 09:24:45PM -0400, Matt Corallo wrote:
> 
> 
> On 6/27/21 21:16, Alan Stern wrote:
> > You mean that only devices in the first group are affected by this bug?
> > Devices in the second group are always detected correctly regardless of
> > what else is plugged in?  (This contradicts what you wrote above.)
> 
> 
> Correct. Ignoring hotplug (ie on fresh boot or lsusb -vvv), the devices in
> the second group work great. The devices in the first group do too, but only
> if a device from the second group is present.

Okay.  You can try collecting some usbmon traces to see what's going on.  

First test: Boot with nothing plugged in, start a usbmon trace for bus 0 
(cat /sys/kernel/debug/usb/usbmon/0u >mon1.txt), plug in a first-group 
device, run lsusb -v to trigger enumeration, and then kill the "cat" 
process.

Second test: Same as the first except that you boot with a second-group 
device already plugged in.

The differences between the two traces may indicate where the problem 
is.

Alan Stern

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  reply	other threads:[~2021-06-28 14:24 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-28  0:32 ODROID-C1/-C2 USB Detection only triggered by some devices Matt Corallo
2021-06-28  0:58 ` Alan Stern
2021-06-28  1:05   ` Matt Corallo
2021-06-28  1:16     ` Alan Stern
2021-06-28  1:24       ` Matt Corallo
2021-06-28 14:24         ` Alan Stern [this message]
2021-06-28 18:37           ` Martin Blumenstingl
2021-06-29 15:05             ` Alan Stern
2021-06-29 15:51               ` Martin Blumenstingl
2021-06-29 16:18                 ` Alan Stern
2021-06-29 16:30                   ` Martin Blumenstingl
2021-06-30  0:35                     ` Alan Stern
2021-07-01 10:03                       ` Anand Moon
2021-07-01 21:18                         ` Martin Blumenstingl
2021-07-02 19:11                           ` Anand Moon
2021-07-02 19:33                             ` Martin Blumenstingl
     [not found]                               ` <CANAwSgQH6HgFQ+xz15AoKhGUF9G18P-cHOVL2FvS_34FrW=bzQ@mail.gmail.com>
2021-07-13 15:41                                 ` Martin Blumenstingl
2021-06-30 23:09                     ` Martin Blumenstingl
2021-07-10 17:07                       ` Martin Blumenstingl
2021-07-11  8:15                         ` ODROID-C1/-C2 USB Detection only triggered by some devices dwc2 Minas Harutyunyan
2021-07-11 17:56                           ` Martin Blumenstingl
2021-07-12  6:42                             ` Minas Harutyunyan
2021-07-12 11:35                               ` Martin Blumenstingl
2021-07-14 15:27                                 ` Minas Harutyunyan
2021-07-14 23:16                                   ` Martin Blumenstingl
2021-07-15  1:44                                     ` Alan Stern
2021-07-15  2:04                                       ` Alan Stern
2021-07-18 21:24                                       ` Martin Blumenstingl
2021-07-19 14:53                                         ` Alan Stern
2021-07-19 15:03                                           ` Alan Stern
2021-07-20 21:55                                           ` Martin Blumenstingl
2021-07-21 15:58                                             ` Alan Stern
2021-08-03 20:20                                               ` Martin Blumenstingl
2021-08-03 21:32                                                 ` Alan Stern
2021-12-12 16:08                                                   ` Martin Blumenstingl
2022-01-10 22:05                                                     ` Martin Blumenstingl

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