CentOS - Feb 2016 - USB Serial ports (ttyACMn) CentOS 6.7 (64-bit) vs. CentOS 6.7 (64-bit)

I have two computers: both running CentOS 6.7, 64-bit, with 
kernel 2.6.32-573.12.1.el6.x86_64.  One is a laptop with an 2 core Intel 
processor and the other is a desktop machine with a 4 core AMD processor. Both 
with selinux enabled.

I have a USB serial port device (a RR-CirKits LCC-Buffer USB).  On the desktop 
I am getting this error:

sauron.deepsoft.com% sudo minicom
Device /dev/ttyACM0 access failed: No such file or directory.
sauron.deepsoft.com% dir -lZ /dev/ttyACM0
crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM0

But it is working on the laptop!

gollum.deepsoft.com% dir -lZ /dev/ttyACM1
crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM1

Same kernel, same device (except it is showing up as ttyACM1 on the laptop).

What is going on here?



-- 
Robert Heller             -- 978-544-6933
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller at deepsoft.com       -- Webhosting Services

I sent this out about a week or so ago, but I have heard nothing. I am
*thinking* it is a SELINUX problem, but I cannot figure out what. The SELINUX
settings for both machines are *exactly* the same (the stock defaults for a
standard CentOS 6 install).  The *only* difference is that the desktop 
(sauron) has a few VMs setup (under KVM) and the laptop (gollum) does not. The 
desktop has an AMD processor and a nVidia video chipset and the laptop has an 
Intel processor and an Intel graphic controller.  Although I can't see how 
either the processor or video chipset would have anything to to with the USB 
or USB serial port-type devices.  The desktop also has a PCI quad serial port 
card and includes the 8250.nr_uarts=8 kernel option and is set up to use an 
analog dialup modem to make PPP connections (again, I don't see that as
having
anything to do with anything).

Both machines are running the same kernel: 2.6.32-573.12.1.el6.x86_64




At Thu, 4 Feb 2016 16:13:33 -0500 Robert Heller <heller at deepsoft.com>
wrote:
> 
> I have two computers: both running CentOS 6.7, 64-bit, with 
> kernel 2.6.32-573.12.1.el6.x86_64.  One is a laptop with an 2 core Intel 
> processor and the other is a desktop machine with a 4 core AMD processor.
Both
> with selinux enabled.
> 
> I have a USB serial port device (a RR-CirKits LCC-Buffer USB).  On the
desktop
> I am getting this error:
> 
> sauron.deepsoft.com% sudo minicom
> Device /dev/ttyACM0 access failed: No such file or directory.
> sauron.deepsoft.com% dir -lZ /dev/ttyACM0
> crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM0
> 
> But it is working on the laptop!
> 
> gollum.deepsoft.com% dir -lZ /dev/ttyACM1
> crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM1
> 
> Same kernel, same device (except it is showing up as ttyACM1 on the
laptop).
> 
> What is going on here?
> 
> 
> 
-- 
Robert Heller             -- 978-544-6933
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller at deepsoft.com       -- Webhosting Services

On Sat, Feb 13, 2016 at 5:14 PM, Robert Heller <heller at deepsoft.com>
wrote:
> I sent this out about a week or so ago, but I have heard nothing. I am
> *thinking* it is a SELINUX problem, but I cannot figure out what. The
SELINUX
> settings for both machines are *exactly* the same (the stock defaults for a
> standard CentOS 6 install).  The *only* difference is that the desktop
> (sauron) has a few VMs setup (under KVM) and the laptop (gollum) does not.
The
> desktop has an AMD processor and a nVidia video chipset and the laptop has
an
> Intel processor and an Intel graphic controller.  Although I can't see
how
> either the processor or video chipset would have anything to to with the
USB
> or USB serial port-type devices.  The desktop also has a PCI quad serial
port
> card and includes the 8250.nr_uarts=8 kernel option and is set up to use an
> analog dialup modem to make PPP connections (again, I don't see that as
having
> anything to do with anything).
>
> Both machines are running the same kernel: 2.6.32-573.12.1.el6.x86_64
>
>
>
>
> At Thu, 4 Feb 2016 16:13:33 -0500 Robert Heller <heller at
deepsoft.com> wrote:
>
>>
>> I have two computers: both running CentOS 6.7, 64-bit, with
>> kernel 2.6.32-573.12.1.el6.x86_64.  One is a laptop with an 2 core
Intel
>> processor and the other is a desktop machine with a 4 core AMD
processor. Both
>> with selinux enabled.
>>
>> I have a USB serial port device (a RR-CirKits LCC-Buffer USB).  On the
desktop
>> I am getting this error:
>>
>> sauron.deepsoft.com% sudo minicom
>> Device /dev/ttyACM0 access failed: No such file or directory.
>> sauron.deepsoft.com% dir -lZ /dev/ttyACM0
>> crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM0
>>
>> But it is working on the laptop!
>>
>> gollum.deepsoft.com% dir -lZ /dev/ttyACM1
>> crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM1
>>
>> Same kernel, same device (except it is showing up as ttyACM1 on the
laptop).
>>
>> What is going on here?
>>
Hi,

Since  you haven't mentioned it, have you checked /var/log/dmesg to
make sure the device number is correct?  (for ex.: cdc_acm 2-1:1.4:
ttyACM0: USB ACM device)
I understand you've come a long way trying to figure this out, but I'd
had my share of hickups when the USB port had been faulty - the device
showed up and the number of the device kept changing.

Also check if there any errors in dmesg when you have just plugged in
the device.

My perms and SELinux context of the USB serial modem are the same, by the way:
ls -laZ /dev/ttyACM1
crw-rw----. root dialout system_u:object_r:tty_device_t:s0

Also, just to make sure sudo settings do not interfere:
sudo -u root -g dialout minicom
Same Error?

One more thing that I would check is to run to make sure I run the
minicom as root:
sudo minicom -s
Minicom's man page says
-s
Setup. Root edits the system-wide defaults in /etc/minirc.dfl with
this option. When it is used, minicom does not initialize, but puts
you directly into the configuration menu. This is very handy if
minicom refuses to start up because your system has changed, or for
the first time you run minicom. For most systems, reasonable defaults
are already compiled in.

Googling revealed another advice - check for the drivers in place:
cat /proc/bus/usb/devices
Found your device there?
It has to have lines with Driver other than "Driver=" and "Driver
=(none)"

This is what I have
...
I:* If#= 2 Alt= 0 #EPs= 0 Cls=02(comm.) Sub=fe Prot=00 Driver=cdc_phonet
I:* If#= 3 Alt= 0 #EPs= 0 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_phonet
I:  If#= 3 Alt= 1 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_phonet
I:* If#= 4 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=cdc_acm
I:* If#= 5 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_acm
...

Oh, and you have mentioned kernel option 8250.nr_uarts=8 - does it
mean you have 8 serial ports on the suaron?
Maybe the device  /dev/ttyACM0 does NOT belong to the device you are
trying to talk to? ( RR-CirKits LCC-Buffer USB ?)

If it is (and I am NOT an expert in serial devices debugging) than
maybe displaying the settings of that port will make you a hint?
stty --file /dev/ttyACM0 --all

Whew, an old technology sure does make you dive deep...

At Sat, 13 Feb 2016 10:14:30 -0500 CentOS mailing list <centos at
centos.org> wrote:
> 
> I sent this out about a week or so ago, but I have heard nothing. I am
> *thinking* it is a SELINUX problem, but I cannot figure out what. The
SELINUX
> settings for both machines are *exactly* the same (the stock defaults for a
> standard CentOS 6 install).  The *only* difference is that the desktop 
> (sauron) has a few VMs setup (under KVM) and the laptop (gollum) does not.
The
> desktop has an AMD processor and a nVidia video chipset and the laptop has
an
> Intel processor and an Intel graphic controller.  Although I can't see
how
> either the processor or video chipset would have anything to to with the
USB
> or USB serial port-type devices.  The desktop also has a PCI quad serial
port
> card and includes the 8250.nr_uarts=8 kernel option and is set up to use an
> analog dialup modem to make PPP connections (again, I don't see that as
having
> anything to do with anything).
OK, I tried rebooting without the '8250.nr_uarts=8' option and that had
no
effect.

I wonder if I should file a bug report?  I don't know if I should file it
with
the Red Hat bugzilla or the CentOS bugzilla.
> 
> Both machines are running the same kernel: 2.6.32-573.12.1.el6.x86_64
> 
> 
> 
> 
> At Thu, 4 Feb 2016 16:13:33 -0500 Robert Heller <heller at
deepsoft.com> wrote:
> 
> > 
> > I have two computers: both running CentOS 6.7, 64-bit, with 
> > kernel 2.6.32-573.12.1.el6.x86_64.  One is a laptop with an 2 core
Intel
> > processor and the other is a desktop machine with a 4 core AMD
processor. Both
> > with selinux enabled.
> > 
> > I have a USB serial port device (a RR-CirKits LCC-Buffer USB).  On the
desktop
> > I am getting this error:
> > 
> > sauron.deepsoft.com% sudo minicom
> > Device /dev/ttyACM0 access failed: No such file or directory.
> > sauron.deepsoft.com% dir -lZ /dev/ttyACM0
> > crw-rw----. root dialout system_u:object_r:tty_device_t:s0
/dev/ttyACM0
> > 
> > But it is working on the laptop!
> > 
> > gollum.deepsoft.com% dir -lZ /dev/ttyACM1
> > crw-rw----. root dialout system_u:object_r:tty_device_t:s0
/dev/ttyACM1
> > 
> > Same kernel, same device (except it is showing up as ttyACM1 on the
laptop).
> > 
> > What is going on here?
> > 
> > 
> > 
> 
-- 
Robert Heller             -- 978-544-6933
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller at deepsoft.com       -- Webhosting Services

On 14/02/16 02:14, Robert Heller wrote:
> I sent this out about a week or so ago, but I have heard nothing. I am
> *thinking* it is a SELINUX problem, but I cannot figure out what.
>
If you suspect SELinux is to blame, have you tried putting SELinux into 
permissive mode to see that resolves the issues?

setenforce 0 (re-enable with setenforce 1)

If everything works with SELinux in permissive mode, then you'll need to 
create a policy for it *[0]*.


ak.

*[0]*: 
https://wiki.centos.org/HowTos/SELinux#head-faa96b3fdd922004cdb988c1989e56191c257c01

At Sun, 14 Feb 2016 19:20:48 -0500 Robert Heller <heller at deepsoft.com>
wrote:
> 
> At Mon, 15 Feb 2016 09:41:32 +1100 CentOS mailing list <centos at
centos.org> wrote:
> 
> > 
> > On 14/02/16 02:14, Robert Heller wrote:
> > > I sent this out about a week or so ago, but I have heard nothing.
I am
> > > *thinking* it is a SELINUX problem, but I cannot figure out what.
> > >
> > 
> > If you suspect SELinux is to blame, have you tried putting SELinux
into
> > permissive mode to see that resolves the issues?
> > 
> > setenforce 0 (re-enable with setenforce 1)
> 
> I guess I can try that.
> 
> > 
> > If everything works with SELinux in permissive mode, then you'll
need to
> > create a policy for it *[0]*.
> 
> That would imply that somehow the policies on my laptop are *different*
than
> the policies on my desktop.  *I* don't remember setting any such
policies...
OK, I just tested it:

sauron.deepsoft.com% sudo /usr/sbin/setenforce permissive
sauron.deepsoft.com% sudo minicom
Device /dev/ttyACM0 access failed: No such file or directory.
sauron.deepsoft.com% sudo /usr/sbin/setenforce enforcing

Nope, that did not help.
> 
> > 
> > 
> > ak.
> > 
> > *[0]*: 
> >
https://wiki.centos.org/HowTos/SELinux#head-faa96b3fdd922004cdb988c1989e56191c257c01
> > 
> > 
> > _______________________________________________
> > CentOS mailing list
> > CentOS at centos.org
> > https://lists.centos.org/mailman/listinfo/centos
> > 
> >                                                                 
> 
-- 
Robert Heller             -- 978-544-6933
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller at deepsoft.com       -- Webhosting Services

I have not yet found a USB-to-serial adapter detected as /dev/ttyACM1.
Try /dev/ttyUSB0 ?

- Mike

On Sat, Feb 13, 2016 at 10:14 AM, Robert Heller <heller at deepsoft.com>
wrote:
> I sent this out about a week or so ago, but I have heard nothing. I am
> *thinking* it is a SELINUX problem, but I cannot figure out what. The
> SELINUX
> settings for both machines are *exactly* the same (the stock defaults for a
> standard CentOS 6 install).  The *only* difference is that the desktop
> (sauron) has a few VMs setup (under KVM) and the laptop (gollum) does not.
> The
> desktop has an AMD processor and a nVidia video chipset and the laptop has
> an
> Intel processor and an Intel graphic controller.  Although I can't see
how
> either the processor or video chipset would have anything to to with the
> USB
> or USB serial port-type devices.  The desktop also has a PCI quad serial
> port
> card and includes the 8250.nr_uarts=8 kernel option and is set up to use an
> analog dialup modem to make PPP connections (again, I don't see that as
> having
> anything to do with anything).
>
> Both machines are running the same kernel: 2.6.32-573.12.1.el6.x86_64
>
>
>
>
> At Thu, 4 Feb 2016 16:13:33 -0500 Robert Heller <heller at
deepsoft.com>
> wrote:
>
> >
> > I have two computers: both running CentOS 6.7, 64-bit, with
> > kernel 2.6.32-573.12.1.el6.x86_64.  One is a laptop with an 2 core
Intel
> > processor and the other is a desktop machine with a 4 core AMD
> processor. Both
> > with selinux enabled.
> >
> > I have a USB serial port device (a RR-CirKits LCC-Buffer USB).  On the
> desktop
> > I am getting this error:
> >
> > sauron.deepsoft.com% sudo minicom
> > Device /dev/ttyACM0 access failed: No such file or directory.
> > sauron.deepsoft.com% dir -lZ /dev/ttyACM0
> > crw-rw----. root dialout system_u:object_r:tty_device_t:s0
/dev/ttyACM0
> >
> > But it is working on the laptop!
> >
> > gollum.deepsoft.com% dir -lZ /dev/ttyACM1
> > crw-rw----. root dialout system_u:object_r:tty_device_t:s0
/dev/ttyACM1
> >
> > Same kernel, same device (except it is showing up as ttyACM1 on the
> laptop).
> >
> > What is going on here?
> >
> >
> >
>
> --
> Robert Heller             -- 978-544-6933
> Deepwoods Software        -- Custom Software Services
> http://www.deepsoft.com/  -- Linux Administration Services
> heller at deepsoft.com       -- Webhosting Services
>
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
>


-- 
---~~.~~---
Mike
//  SilverTip257  //

On 16/02/16 01:32, Robert Heller wrote:
> OK, I just tested it:
>
> sauron.deepsoft.com% sudo /usr/sbin/setenforce permissive
> sauron.deepsoft.com% sudo minicom
> Device /dev/ttyACM0 access failed: No such file or directory.
> sauron.deepsoft.com% sudo /usr/sbin/setenforce enforcing
>
> Nope, that did not help.
>
When using my USB to serial device I've had to make sure that I'm a 
member of the 'dialout' group.  Even though you are using sudo to run 
minicom, could it be that the user account you are logged in as still 
needs to be a member of the dialout group?  (tol - thinking out loud)


ak.