Re: Preventing modem-manager from accessing specific serial ports?
On 24/10/13 04:37, Volker Kuhlmann wrote: http://cgit.freedesktop.org/ModemManager/ModemManager/tree/src/77-mm-usb-device-blacklist.rules Thank you very much Dan, adding ID_MM_DEVICE_IGNORE is trivial once one knows that is the trick to use. Are there *any* modems using any of the FTDI USB/serial converters? Or does MM handle the old serial port modems too? Because if not, modem manager should perhaps be shipped with a blacklist rule for those because it can never do any good with them. MM supports plain RS232 modems (e.g. some Cinterion ones or Iridium satellite modems). In MM 0.6.x we had a blacklist for serial devices which are definitely not modems. In this list we (upstream) didn't include USB-RS232 adapters, although several distributions then added those in the blacklist when packaging (therefore removing support for RS232 modems connected via USB-RS232 adapters). To solve this issue and avoid having distros ship additional blacklist rules, in MM 1.x we added an additional 'greylist', so that we have: * a blacklist for serial devices which are definitely not modems (as we had in 0.6.x upstream) * a greylist for USB-RS232 adapters, as they may have a RS232 modem behind. In this setup, MM will never probe the blacklisted ones, and will only probe the greylisted ones if a manual Scan() is requested (i.e. never automatically). Setups using MM with a RS232 modem will anyway need a periodic explicit Scan() to detect whether there is a modem in the serial port (both with platform ports and for USB-RS232 adapters), so applying the greylist only for this case is actually appropriate. -- Aleksander ___ networkmanager-list mailing list networkmanager-list@gnome.org https://mail.gnome.org/mailman/listinfo/networkmanager-list
Re: Preventing modem-manager from accessing specific serial ports?
On Sun 20 Oct 2013 08:43:57 NZDT +1300, Dan Williams wrote:
http://cgit.freedesktop.org/ModemManager/ModemManager/tree/src/77-mm-usb-device-blacklist.rules
Thank you very much Dan, adding ID_MM_DEVICE_IGNORE is trivial once one
knows that is the trick to use.
Are there *any* modems using any of the FTDI USB/serial converters? Or
does MM handle the old serial port modems too? Because if not, modem
manager should perhaps be shipped with a blacklist rule for those
because it can never do any good with them.
copy that file, change it as appropriate, and put it
into /etc/udev/rules.d. Note the match on usb_device, which is the
key part here that applies the tag to the usb device object instead of
the TTYs that hang off it.
Here's a snag:
I use rules like (1 line)
SUBSYSTEMS==usb, ATTRS{idVendor}==0403, ATTRS{idProduct}==6001,
ATTRS{manufacturer}==FTDI, ATTRS{product}==FT232R USB UART,
ATTRS{serial}==A60x, SYMLINK+=ttyUSB_somename
without any other qualification so I can access my hardware by
ttyUSB_somename without having to care what number the kernel assigned
this time.
Appending ENV{ID_MM_DEVICE_IGNORE}=1 to that keeps MM off.
Bracketing this with
ACTION!=add|change, GOTO=AVR_FTDI_rules_end
is fine, however, bracketing this with either one of
SUBSYSTEM!=usb, GOTO=AVR_FTDI_rules_end
ENV{DEVTYPE}!=usb_device, GOTO=AVR_FTDI_rules_end
causes the symlinks to be created like this:
crw-rw /dev/ttyUSB0
lrwxrwxrwx /dev/ttyUSB_somename - bus/usb/001/041
which is useless.
What happens exactly if I don't qualify the symlink rule by
SUBSYSTEM==usb, ENV{DEVTYPE}==usb_device? I don't currently have a
modem to try this with.
Thanks again,
Volker
--
Volker Kuhlmann
http://volker.dnsalias.net/ Please do not CC list postings to me.
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Re: Preventing modem-manager from accessing specific serial ports?
On Sat, 2013-10-19 at 09:07 +1300, Volker Kuhlmann wrote: I have a bunch of Arduino hardware that connects with emulated serial ports using FTDI chips (there are other possibilities for serial port emulation too, e.g. CP2102 or microcontroller based ones). As soon as I plug one of these devices in, modem-manager becomes active and probes the devices, timing out each time (of course) and retrying that about 3 times. This interferes with the serial port being used by Arduino or terminal software. What is the mechanism to tell modem-manager to keep its hands off FTDI-based serial ports? I have used udev rules to create constant-name device symlinks based on the devices USB IDs and serial number. I realise that modems use emulated serial ports too so there is always conflict, but I am not sure whether there are modems using devices for which the device name is /dev/ttyUSBN. I'd be happy to configure exclusion lists, but how do I do this? A ton of modems will actually get assigned /dev/ttyUSBx by the kernel; using device names is also usually a bad idea, because the kernel is quite happy to renumber them all when you plug a different device in, or if something goes wrong (driver wedges, etc) and you unplug/replug. Symlinks aren't a solution here either, because the kernel will still assign the same device name (eg ttyUSBx) to the devices. So, you blacklist the entire USB device by whatever attributes you want to use (often VID/PID, but could be anything else sysfs exposes), not just the specific serial ports, because many devices expose multiple serial ports. The default examples are here: http://cgit.freedesktop.org/ModemManager/ModemManager/tree/src/77-mm-usb-device-blacklist.rules copy that file, change it as appropriate, and put it into /etc/udev/rules.d. Note the match on usb_device, which is the key part here that applies the tag to the usb device object instead of the TTYs that hang off it. Dan There also seems to be a difference between desktop and laptop computers. Modem-manager activates only on the laptop. Thanks, Volker ___ networkmanager-list mailing list networkmanager-list@gnome.org https://mail.gnome.org/mailman/listinfo/networkmanager-list
Preventing modem-manager from accessing specific serial ports?
I have a bunch of Arduino hardware that connects with emulated serial ports using FTDI chips (there are other possibilities for serial port emulation too, e.g. CP2102 or microcontroller based ones). As soon as I plug one of these devices in, modem-manager becomes active and probes the devices, timing out each time (of course) and retrying that about 3 times. This interferes with the serial port being used by Arduino or terminal software. What is the mechanism to tell modem-manager to keep its hands off FTDI-based serial ports? I have used udev rules to create constant-name device symlinks based on the devices USB IDs and serial number. I realise that modems use emulated serial ports too so there is always conflict, but I am not sure whether there are modems using devices for which the device name is /dev/ttyUSBN. I'd be happy to configure exclusion lists, but how do I do this? There also seems to be a difference between desktop and laptop computers. Modem-manager activates only on the laptop. Thanks, Volker -- Volker Kuhlmann http://volker.dnsalias.net/ Please do not CC list postings to me. ___ networkmanager-list mailing list networkmanager-list@gnome.org https://mail.gnome.org/mailman/listinfo/networkmanager-list
