Needs root? #24

MartinPaulEve · 2017-09-07T14:42:08Z

OK, this is probably a silly question, but is there a way to avoid the need for root on Linux systems? My device isn't detected unless I run with sudo...

I added the following udev rule, but no luck:

ACTION=="add", SUBSYSTEMS=="usb", ATTRS{idVendor}=="1235", ATTRS{idProduct}=="0036", MODE="660", GROUP="plugdev"

This is a Launchpad Mini Mk2

FMMT666 · 2017-09-07T17:13:22Z

So "isn't detected" means that "lp.ListAll()" does not see anything
or do you mean the kernel messages (e.g. output from "dmesg")?

Are you member of a group that allows access to audio (and MIDI) devices,
something like "audio", etc...
What distro are you using?

MartinPaulEve · 2017-09-07T17:39:24Z

Hi, Thanks for reply. The device is detected just fine by the kernel and when I run, say, example.py as root everything works as expected. It's just that, as a normal user, the script can't connect. It's Ubuntu 17.04. User is a member of the audio and plugdev groups. Any advice much appreciated - and thanks so much for your great work with this library. Martin

…

On Thu, 7 Sep 2017, 18:13 FMMT666 ***@***.***> wrote: So "isn't detected" means that "lp.ListAll()" does not see anything or do you mean the kernel messages (e.g. output from "dmesg")? Are you member of a group that allows access to audio (and MIDI) devices, something like "audio", etc... What distro are you using? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#24 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA_ot2lAEcqbV4nDjtCv8F9pnjlWroCiks5sgCQzgaJpZM4PP60f> .

FMMT666 · 2017-09-07T20:55:08Z

Will check that this weekend...
Do you have Jack installed?

MartinPaulEve · 2017-09-07T20:59:45Z

No Jack in this install. Pulse audio...

…

On Thu, 7 Sep 2017, 21:55 FMMT666 ***@***.***> wrote: Will check that this weekend... Do you have Jack installed? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#24 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA_ot9WJt_DUMRPj3gVIZ1OWqraUHkuFks5sgFgtgaJpZM4PP60f> .

FMMT666 · 2017-09-09T16:58:11Z

Mhh, that even works w/o being a member of audio/plugdev/orwhatever
(on my 16.04 systems).

Did you eventually install any driver for the Launchpads?
That's usually not necessary and might cause problems.

What exactly does happen? What does lp.ListAll() print?
Do at least the Midi through ports appear?

('ALSA', 'Midi Through Port-0', 0, 1, 0)
('ALSA', 'Midi Through Port-0', 1, 0, 0)

You can also check your permissions or installation with "aconnect -i":

Client 0: 'System' [Typ=Kernel]
    0 'Timer           '
    1 'Announce        '
Client 14: 'Midi Through' [Typ=Kernel]
    0 'Midi Through Port-0'
Client 20: 'Launchpad Mini' [Typ=Kernel]
    0 'Launchpad Mini MIDI 1'

and later with that number of the device above (here it's "20"):
"aseqdump -p 20":

Waiting for data. Press Ctrl+C to end.
Source  Event                  Ch  Data
 20:0   Note on                 0, note 36, velocity 127
 20:0   Note off                0, note 36
 20:0   Note on                 0, note 36, velocity 127
 20:0   Note off                0, note 36
 20:0   Note on                 0, note 52, velocity 127
 20:0   Note off                0, note 52

Does that work? Can you access the Launchpad that way?

MartinPaulEve · 2017-09-10T08:43:00Z

OK, so:

Running this:

lp = launchpad.Launchpad()
print(lp.ListAll())
return

returns

None
ALSA lib conf.c:3009:(snd_config_update_r) Cannot access file /etc/alsa/alsa.conf
ALSA lib seq.c:935:(snd_seq_open_noupdate) Unknown SEQ default
Exception AttributeError: "'NoneType' object has no attribute 'quit'" in <bound method __Midi.del of <launchpad_py.launchpad.__Midi instance at 0x7fdccef4b2d8>> ignored

Does it need an alsa config file in /etc/alsa/alsa.conf?

When I do aconnect -i:

[ martin: ~ ]$ aconnect -i
client 0: 'System' [type=kernel]
0 'Timer '
1 'Announce '
client 14: 'Midi Through' [type=kernel]
0 'Midi Through Port-0'
client 24: 'M-Track 2X2M' [type=kernel,card=2]
0 'M-Track 2X2M MIDI 1'
client 28: 'Launchpad Mini' [type=kernel,card=3]
0 'Launchpad Mini MIDI 1'

When I do aseqdump -p 28:

[ martin: ~ ]$ aseqdump -p 28
Waiting for data. Press Ctrl+C to end.
Source Event Ch Data
28:0 Note on 0, note 39, velocity 127
28:0 Note off 0, note 39
28:0 Note on 0, note 49, velocity 127
28:0 Note off 0, note 49

So that all seems to work. It's just that the python script can't seem to access the device without root. (Script is being run under the same user account -- martin -- as was aseqdump)

MartinPaulEve · 2017-09-10T08:45:01Z

Here's a comparison of them running with root and without:

(launchControl) [ martin: ~/Documents/Programming/launchPadControl ]$ sudo python ./launcher.py [sudo] password for martin: ('ALSA', 'Midi Through Port-0', 0, 1, 0) ('ALSA', 'Midi Through Port-0', 1, 0, 0) ('ALSA', 'M-Track 2X2M MIDI 1', 0, 1, 0) ('ALSA', 'M-Track 2X2M MIDI 1', 1, 0, 0) ('ALSA', 'Launchpad Mini MIDI 1', 0, 1, 0) ('ALSA', 'Launchpad Mini MIDI 1', 1, 0, 0) None (launchControl) [ martin: ~/Documents/Programming/launchPadControl ]$ python ./launcher.py ALSA lib conf.c:3009:(snd_config_update_r) Cannot access file /etc/alsa/alsa.conf ALSA lib seq.c:935:(snd_seq_open_noupdate) Unknown SEQ default None Exception AttributeError: "'NoneType' object has no attribute 'quit'" in <bound method __Midi.__del__ of <launchpad_py.launchpad.__Midi instance at 0x7fe9cf482320>> ignored

MartinPaulEve · 2017-09-10T08:58:02Z

Right, solved it!

I added an alsa config file that reads:

`seq.default {
type hw
}

seq.hw {
type hw
}
`

Now it works without root. Perhaps adding this to an FAQ/the docs in case anyone else hits it?

Thanks so much again for your work on this library!

FMMT666 · 2017-09-10T14:38:54Z

Great work, thanks!

Seems identical to #21.
PyGame was obviously built with an older Alsa version...

If you have got a little time, could you please do me a favour
and create a symbolic link from /etc/alsa/also.conf to your already existing
alsa.conf in /usr/share/alsa/alsa.conf and test whether that works?

sudo ln -s /usr/share/alsa/alsa.conf /etc/alsa/alsa.conf

(I assume you know how to do that. Just posting that for
the sake of completeness ;-)

I also just installed Ubuntu 17.04 in a VM (skipping localization ragequits here)
for a further analysis (although I guess, the best solution is just to move
over to rtmidi/2 and drop PyGame).

MartinPaulEve · 2017-09-10T14:42:04Z

No worries!

I can confirm that symlinking the default alsa configuration does not work. (No launchpads detected.)

FMMT666 · 2017-09-10T14:47:34Z

Thanks a lot!
Yep, same on my VM setup, but as it seems, that worked
for others (though I don't know whether they were using
an Ubuntu flavoured OS).

MartinPaulEve · 2017-09-10T14:53:42Z

Yeah, sorry for not spotting the alsa output error earlier when I first made this post.

Is there a way to provide alsa parameters to pygame? That could solve it without wholesale replacing the library...

FMMT666 · 2017-09-10T15:28:12Z

PyGame uses PortMidi (which itself uses Alsa under Linux, Core MIDI under macOS and
MME in Windoze) and actually I'm quite surprised that it still works on 2017's HW
and OSs :-). It was last (officially) updated somewhere around 2010...

FMMT666 · 2017-09-11T21:10:24Z

Added your solution to the doc, including a mention.
Hope you're ok with that...

Thanks!

MartinPaulEve · 2017-09-12T09:23:03Z

That's great -- thanks so much!

…

On 11/09/17 22:10, FMMT666 wrote: Added your solution to the doc, including a mention. Hope you're ok with that... Thanks! — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#24 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA_ot1PWP2uljJMZgzVgUIwKJq9ZEkZLks5shaHBgaJpZM4PP60f>.

-- Professor Martin Paul Eve Chair of Literature, Technology and Publishing Birkbeck, University of London T: 0203 073 8420 E: [email protected] W: https://www.martineve.com R: 416, 43 Gordon Square, London, WC1H 0PD Books: https://www.martineve.com/books/ Articles: https://www.martineve.com/c-v/ Series Editor: New Horizons in Contemporary Writing (Bloomsbury) Director, Birkbeck Centre for Technology and Publishing Founder, Open Library of the Humanities (https://www.openlibhums.org) Chief Editor, Orbit (https://www.pynchon.net) Senior Online Editor, Alluvium, (http://www.alluvium-journal.org)

ewpratten · 2024-05-09T15:22:16Z

For Fedora users: This seems to work on F39

sudo mkdir -p /usr/local/share/alsa
sudo ln -s /usr/share/alsa/alsa.conf /usr/local/share/alsa/alsa.conf

FMMT666 closed this as completed in 40bcfcb Sep 11, 2017

FMMT666 mentioned this issue Sep 11, 2017

Linux Issue #23

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Needs root? #24

Needs root? #24

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Needs root? #24

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