Caveats for audio in 9.10

Here follows an update for 9.10 to this month's earlier caveats:

If you use Ubuntu:

• Use Karmic's kernel, not Jaunty's. A lot of you with Realtek and IDT/Sigmatel HDA codecs are being bitten by /boot/grub/grub.cfg not being updated properly, resulting in Jaunty's 2.6.28 kernel being used instead of Karmic's 2.6.31. Jaunty's kernel has pretty subpar performance for PulseAudio, and you should not incorrectly blame PulseAudio.
• Check that slmodemd is not running if you're seeing a dummy/null sink in the volume control applet. Arguably PulseAudio's module-udev-detect should allow the device instead of bailing when detecting it, and an approach is under discussion for future versions. In the meantime, you can either instead load module-detect in /etc/pulse/default.pa (or ~/.pulse/default.pa) or kill slmodemd.
• Install linux-backports-modules-alsa-karmic (then reboot) if you have a very new computer, because that package enables audio on quite a few very new laptop models and contains much improved support for microphone auto-switching.
• Use a temporary alternate channel mapping for PulseAudio if you have an ice17xx-based sound card. Please be aware that the fault lies with alsa-lib not PulseAudio and will be addressed in 10.04 LTS.
• Configure PulseAudio to ignore your sound driver's misreported dB information if you experience "overdriven" sound.
• Attach a verbose PulseAudio runtime log to your PulseAudio bug report.
• Attach an ALSA codec dump to your linux bug report if jack sense (e.g., connecting headphones mutes internal laptop speakers) does not seem to function properly.

As always, thank you for helping improve Ubuntu!

The perils of saving sound card state; and why apologizing is good.

Bad news: I broke alsa-utils in Karmic.

Good news: I fixed it tonight. Please report your results.

Honestly, I tested the previous upload on Ubuntu, Kubuntu, and Xubuntu before committing to bzr -- even on different hardware! It just goes to show that I make dumb mistakes, so, sorry about that.

Mo' bett' news: many thanks to the awesome Tim Gardner, who imported alsa-driver stable (snapshot from 20091012) into ubuntu-karmic-lbm.git, which means that all you poor saps with eeePCs and HP dvs and Dell Studios will finally have less suck for audio. Granted, it will require installing linux-backports-modules-karmic in a week or so...

In other news (what?! there're more kinds?!), it really is decent to apologize when I make mistakes. This guy is a real gem, that is all.

Caveats for audio in Ubuntu Karmic Beta

In the wake of the Ubuntu Karmic Beta release, here are some audio gotchas on my radar:

* Volumes being erroneously set to 0 and/or muted upon reboot/shutdown
** We'll address this in Lucid by altering how alsactl store is called. For Ubuntu, there's arguably no need to actually call alsactl restore; PulseAudio handles volume state on its own. Granted, the approach will take some fleshing out, as we need to handle Kubuntu, Xubuntu, Ubuntu Studio, ...

* Default PulseAudio behaviour causes overdriven audio due to hardware inanity
** Thanks to some wonderful (sarcasm) hardware integration, we can work around this issue by using the patch mentioned in the comment. Please note that this patch will not be turned on for Karmic, because doing so will result in a very poor user experience for many more HDA users whose hardware are not quite so craptastic.

* Internal/External microphone selection is broken for many HDA users
** Well-known upstream, being addressed for Lucid, patches too invasive for Karmic, etc.

* Extremely high CPU usage by PulseAudio with third-party applications (Skype, I'm looking at you)
** Use the PulseAudio-aware beta of Skype

Finally, last post I described populating the alsactl init database. There are a few things of which one should be aware:

* Too quiet or too loud is usually a driver (i.e., linux) bug
** We can work around this in alsa-kernel/linux, so the first place we check is linux, not alsa-utils. In the rare case it is not a driver bug, we resort to alsactl init patches.

* You can clone the upstream alsa-utils git tree and submit patches directly
** (Next post, I'll cover how to do it.)

Atlanta Linux Fest 2009 and Crowdsourcing

A couple months ago, upon reading the tentative speaker schedule for Atlanta Linux Fest 2009, I was surprised at the Canonical omnipresence. There was personal trepidation regarding how such a presence may be interpreted, and sure enough, I wasn't alone. Certainly in my talk, I kept the vast majority of the physical speech focused on current FOSS and mentioned Ubuntu only in the confines of what we've done poorly and how we're resolving those shortcomings.

For instance, one of the most difficult things to "get right" in a default (clean) install is configuring various audio settings. A great analogous post by Ed Felten really made me reconsider the command line as the preferable interface for troubleshooting.

Many parts of Ubuntu are contributed by volunteers (thank you!) like myself. There seems to be a considerable amount of bad blood in the Linux community regarding what Canonical "doesn't do". We all need to do a better job of thanking our fellow volunteers and remembering that corporate overlords do not drive everything.

That said, I enjoyed the brief moments spent at this year's ALF (had to leave early to return to work), particularly the thoughtfulness of all the organizers (please thank them!) and attendees.

See you this weekend at Ohio LinuxFest!

Limited liability, or how not to develop Karmic using Karmic

Karmic has been wonderfully jumpy these past few days. I must have some sick fascination with broken systems, as my presentation at this year's Ohio LinuxFest will focus on developing Karmic while running Karmic. Not just that, but this Saturday I'll briefly discuss Linux audio at Atlanta Linux Fest.

Now for the real meat in this post. For Karmic+1, I want Ubuntu to lead the charge in populating alsa-utils's init db.

Currently we do some pretty braindead things in alsa-utils's initscript, namely forcibly iterate over an entire set of static mixer element strings and values and attempt to set all detected audio devices to a specific state. Well, it's rather unlikely that my Logitech USB headset will have a Creative Audigy-specific "Audigy Analog/Digital Output Jack", yes?

Of course, that's just one badness, but the driving factor is to be able to conditionally set volumes on system start (for non-PulseAudio configurations) based on the machine's SSID. This approach largely resolves the "Gee, I have an Audigy X that requires the jack toggle to be muted to get audible analog output but person Y with an Audigy Z requires it to be unmuted" debacle.

So where do you come in? With current HDA codecs, using a static setting of 80% for PCM is pretty fragile. Some hardware sounds really overdriven at that setting, and others are barely audible. We need your SSID (lspci -nv|grep -A1 040[13]) and your preferred volumes! More in the following weeks.

"Meanwhile, in real life"...

Firstly, I have been neglecting my Ubuntu Karmic objectives due to a sudden fit of productivity in $dayjob. I expect this lapse to be completed after the Black Hat USA briefings. (That said, if you're headed to that Sin City and have Ubuntu sound problems, find me, and we can eliminate the debugging roundtrips.)

Secondly, I am working through the powerdown issues for the remaining HDA (controllers and) codecs besides Sigmatel/IDT. The Analog Devices and Realtek ones are pains in my rear.

Lastly, some words on respect. I tend toward forcefulness - sometimes misled but mostly well-intentioned - and note that, rather than blow much hot air about the (emotional) fitness of Mono or the blatant sexism in many environments (not just FOSS), to frame the issues as obstinate juvenile mutterings reduces them to the bottom line: I (we) disrespect other people. I (we) should stop being an idiot(s). But rather than argue who needs to stop what, I am going to eradicate the tomfoolery and shenanigans that I have internalised. It's really simple: people notice when I (we) take time to help them with Ubuntu. People notice when I (we) take time to note that I (we) don't agree with sexism in presentations. For me, Ubuntu is about leading through maturity.

Action items from UDS Barcelona

As usual, the Ubuntu Developers Summit was a whirlwind, and I returned to the States enthusiastic about making Karmic a better user experience.

On the audio front, a slew of bugs have been resolved in Karmic simply by upgrading the entire stack. I led a plenary session during UDS focused on the travails of audio in Linux [OpenOffice.org presentation] with emphasis on how they affect Ubuntu and its remixes. Soon Luke and I will be offering snapshot builds in a dedicated audio PPA of alsa-driver-stable (daily), alsa-driver-unstable (daily), and pulseaudio (weekly). These pristine builds will contain only minimal packaging bits to facilitate debugging with respective upstreams. The availability of test builds of PulseAudio will make it easier to ship the most recent stable version in Karmic.

Roderick Greening and I will be testing GStreamer with PulseAudio on Kubuntu as part of the effort to streamline the audio stack. There will be a separate PPA for these packages.

Glitch-free PulseAudio likely will not be enabled in Karmic. There is insufficient traction in changing kernel configuration options, and we will all need to evaluate how those configurations affect other objectives (e.g., improved battery life).

As part of an improved battery life objective, powering down HDA controller amps when no sound is being played has already been enabled. The mailing list post covers possible regressions and how to track development with your experiences.

On the community front, something that has plagued the distribution process-wise is the heavyweight handling of patches from contributors. Patches, even URLs to them, often languish in Launchpad despite being tagged as containing patches. Both drive-by contributions and fully Debianised/Ubuntuised debdiffs suffer this same fate. I've taken on the task of making sure the process for people not immersed in the Ubuntu development model is more akin to a front office or reception similar to MOTU mentorship. Instead of expecting new contributors to follow the distribution's development model, a new Launchpad group, ubuntu-reviewers, with an associated mailing list, will be responsible for taking posted references to git changesets, patch URLs, etc., converting them into usable debdiffs for the appropriate Ubuntu release(s), and subscribing the appropriate component sponsor group. For example, if you find a bugfix for a package, you could send an e-mail to the mailing list for said review group. You could also file a bug using ubuntu-bug/Launchpad, clearly state the URL to the patch, and subscribe the review group.

While the administrative work is in progress (e.g., name of the Launchpad group), the goal is straightforward: involve as many contributors as possible without bogging them down in, well, administrivia.