| * shriekout $decode(s60gwKe068fRILDHtOPAzLTZISEhDQpuaWNrILDHtOMNCnF1aXQgOrDHtOMgx9ewocfXsKE=,m) | 03:11 | |
| === yofel_ is now known as yofel | ||
| === mac_v is now known as \vish | ||
| crimsun | (sorry, waylaid by travel wifi) | 22:16 |
|---|---|---|
| crimsun | Welcome to this $timeofday's impromptu session on triaging ALSA bugs in Ubuntu and submitting fixes upstream | 22:17 |
| crimsun | A couple things to note: you'll need ubuntu-dev-tools, patchutils, git-core installed | 22:17 |
| crimsun | you'll also need some familiarity with C, though it doesn't need to be deep magic guru stuff | 22:18 |
| crimsun | Agendum: 1. Low-hanging fruit: bugs with known-working quirks commented in the bug reports | 22:19 |
| crimsun | 2. Not really fruit: Powerdown bugs | 22:19 |
| crimsun | 3. Submitting patches upstream | 22:19 |
| crimsun | Some required reading: https://wiki.ubuntu.com/DebuggingSoundProblems, in particular https://wiki.ubuntu.com/DebuggingSoundProblems/KarmicCaveats | 22:21 |
| crimsun | Next, free space requirements: you'll need about 300 MB free for git trees | 22:22 |
| crimsun | We'll be checking out three git trees: upstream linux-2.6 (Linus's tree), sound-2.6 (upstream ALSA kernel tree), ubuntu-lucid | 22:24 |
| crimsun | After ensuring that you have the prerequisites above installed, you'll do: | 22:24 |
| crimsun | git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git linux-2.6.git | 22:24 |
| crimsun | then: | 22:25 |
| crimsun | git clone --referenc linux-2.6.git/ git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6.git | 22:25 |
| crimsun | sorry, that's --reference | 22:25 |
| crimsun | then: git clone --reference linux-2.6.git/ git://kernel.ubuntu.com/ubuntu/ubuntu-lucid.git | 22:26 |
| crimsun | Let's look at examples in the meantime (if you're waiting for them to complete) | 22:27 |
| apparle | crimsun: can I interrupt | 22:28 |
| crimsun | https://bugs.launchpad.net/bugs/487884 | 22:28 |
| ubot2 | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] | 22:28 |
| ubottu | Ubuntu bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] | 22:28 |
| ubot2 | Ubuntu bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:28 |
| ubottu | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:28 |
| ubot2 | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:28 |
| crimsun | apparle: can it wait for about 10 minutes? | 22:29 |
| apparle | crimsun: no problem... | 22:29 |
| crimsun | apparle: thanks | 22:30 |
| crimsun | So, some background: | 22:30 |
| crimsun | there are a lot of AC'97 codecs that need some sort of quirk applied | 22:30 |
| crimsun | About four to five years ago, I spent a good long while getting the most common ones applied | 22:31 |
| crimsun | Those were mostly binding of 'Master' and 'Headphone' mixer controls and binding 'Headphone' to an indicator LED (for mute status) | 22:32 |
| crimsun | These days, for AC'97, we'll see a few stragglers that need inverted external amplifier power down (EAPD) applied | 22:32 |
| crimsun | This symptom most frequently manifests itself in needing 'External Amplifier' to be muted for sound to be audible. | 22:33 |
| crimsun | There's an existing quirk for this called inv_eapd | 22:33 |
| crimsun | If you were to pass this option on the command line or in /etc/modprobe.d/alsa-base.conf, it would look similar to: | 22:34 |
| crimsun | ac97_quirk=inv_eapd | 22:34 |
| crimsun | e.g., modprobe snd-intel8x0 ac97_quirk=inv_eapd | 22:34 |
| crimsun | [after which point you could use 'External Amplifier' being unmuted for sound to be audible, which is the accepted norm] | 22:35 |
| crimsun | most AC'97 quirks live in their respective drivers | 22:36 |
| crimsun | the three most common ones are sound/pci/intel8x0.c, sound/pci/atiixp.c, and sound/pci/via82xx.c [though there are numerous others in sound/pci/] | 22:37 |
| crimsun | so, for bug 487884, we're looking specifically at applying this quirk | 22:37 |
| ubot2 | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:37 |
| ubottu | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:37 |
| ubot2 | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:37 |
| ubottu | Ubuntu bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] | 22:37 |
| ubot2 | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] | 22:37 |
| ubottu | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:37 |
| ubot2 | Ubuntu bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:37 |
| crimsun | http://launchpadlibrarian.net/36040747/Card0.Codecs.codec97.0.ac97.0.0.txt has the important information | 22:38 |
| crimsun | Namely, we need the PCI SSID, which in this case is 0x161f203a | 22:39 |
| crimsun | we next look at the source file that needs to be modified, which is sound/pci/intel8x0.c | 22:39 |
| crimsun | at this point, we should change working directories to wherever we cloned ubuntu-lucid.git | 22:40 |
| crimsun | next, we'll create a separate branch (some people use topic namespace) | 22:40 |
| crimsun | $ git checkout -b lp487884 | 22:40 |
| crimsun | then, we'll edit the source file | 22:41 |
| crimsun | $ $EDITOR sound/pci/intel8x0.c | 22:41 |
| crimsun | AC'97 quirks live in the ac97_quirks[] struct, and they should be ordered by subvendor ID | 22:41 |
| crimsun | From this point the addition should be fairly straightforward. Add another stanza, fill in the human-friendly model name, add the quirk type | 22:42 |
| crimsun | $ git commit -a -e -s | 22:42 |
| crimsun | The first line of your commit message should briefly describe the change | 22:43 |
| crimsun | ALSA: intel8x0: Mute External Amplifier by default for Gateway 4525GZ | 22:43 |
| crimsun | the next line (delimited by a blank line) should be the BugLink id, which is something that is Ubuntu syntax-specific for the kernel team | 22:44 |
| crimsun | BugLink: https://bugs.launchpad.net/bugs/487884 | 22:44 |
| ubot2 | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] | 22:44 |
| ubottu | Ubuntu bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] | 22:44 |
| ubot2 | Ubuntu bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:44 |
| ubottu | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:44 |
| ubot2 | Launchpad bug 487884 in linux "No sound driver for Gateway 4525GZ" [Low,Fix committed] https://launchpad.net/bugs/487884 | 22:44 |
| crimsun | Next, describe the change: | 22:44 |
| crimsun | This Gateway model needs External Amplifier muted for audible playback, | 22:44 |
| crimsun | so set the inv_eapd quirk for it. | 22:44 |
| crimsun | . | 22:45 |
| crimsun | Make sure that you keep lines wrapped at 80 characters; many maintainers prefer 72 characters. | 22:45 |
| crimsun | Finally, if the change is very simple (like this one), then you should submit it to the stable tree so that it ends up in Ubuntu | 22:46 |
| crimsun | Above your Signed-off-by line you should have: | 22:46 |
| crimsun | CC: stable@kernel.org | 22:46 |
| crimsun | . | 22:47 |
| crimsun | After saving your commit message, the change will be committed, and you can generate a patch to send upstream. | 22:47 |
| crimsun | There are several ways of doing this, but upstream ALSA likes separate patches. | 22:47 |
| crimsun | So, we'll use: | 22:48 |
| crimsun | git format-patch -o ~ master | 22:48 |
| crimsun | You'll end up with ~/0001-ALSA-... | 22:48 |
| crimsun | This is the patch that you'll attach to your e-mail message. The e-mail should be sent to alsa-devel@alsa-project.org, with Takashi Iwai and myself CCed | 22:50 |
| crimsun | And that's pretty much the process for bite-sized fixes. | 22:50 |
| crimsun | apparle: you're up | 22:51 |
| apparle | got it clear | 22:51 |
| apparle | but I am having a problem | 22:51 |
| apparle | what to do abt this | 22:51 |
| apparle | git.kernel.org[0: 149.20.20.136]: errno=Connection refused git.kernel.org[0: 199.6.1.166]: errno=Connection refused git.kernel.org[0: 204.152.191.40]: errno=Connection refused git.kernel.org[0: 130.239.17.7]: errno=Connection refused fatal: unable to connect a socket (Connection refused) | 22:51 |
| apparle | I am behing a stringent firewall(university) | 22:52 |
| crimsun | apparle: you'll need to use another protocol, then, like http | 22:52 |
| crimsun | (which is unfortunate, because it's less optimized, but it's one of the few ways to continue if you're behind a firewall) | 22:53 |
| apparle | Initialized empty Git repository in /home/apparle/linux-2.6.git/.git/ fatal: http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git/info/refs download error - Failed connect to git.kernel.org:80; Operation now in progress | 22:54 |
| apparle | what to do? | 22:54 |
| crimsun | apparle: firewalls are a bit beyond the scope of this discussion | 22:55 |
| crimsun | in brief, see git-clone(1)'s "GIT URLS" section for a description | 22:55 |
| apparle | crimsun: you mean in the man page? | 22:56 |
| crimsun | apparle: yes | 22:56 |
| crimsun | Okay, continuing. | 22:56 |
| crimsun | The next bug we'll consider is no more difficult, but it moves into problematic areas of HDA. | 22:57 |
| crimsun | In bug 461062, we need to ensure that the reporter's hardware doesn't suffer from distortion when the PCM volume is set to max. | 22:58 |
| ubot2 | Launchpad bug 461062 in linux "0x11d41981 on 0x103c30d8 misreports dB information, needs PCM capped at 0 dB" [Undecided,Fix committed] https://launchpad.net/bugs/461062 | 22:58 |
| ubottu | Launchpad bug 461062 in linux "0x11d41981 on 0x103c30d8 misreports dB information, needs PCM capped at 0 dB" [Undecided,Fix committed] https://launchpad.net/bugs/461062 | 22:58 |
| ubot2 | Launchpad bug 461062 in linux "0x11d41981 on 0x103c30d8 misreports dB information, needs PCM capped at 0 dB" [Undecided,Fix committed] | 22:58 |
| ubottu | Ubuntu bug 461062 in linux "0x11d41981 on 0x103c30d8 misreports dB information, needs PCM capped at 0 dB" [Undecided,Fix committed] | 22:58 |
| ubot2 | Launchpad bug 461062 in linux "0x11d41981 on 0x103c30d8 misreports dB information, needs PCM capped at 0 dB" [Undecided,Fix committed] https://launchpad.net/bugs/461062 | 22:58 |
| ubottu | Launchpad bug 461062 in linux "0x11d41981 on 0x103c30d8 misreports dB information, needs PCM capped at 0 dB" [Undecided,Fix committed] https://launchpad.net/bugs/461062 | 22:58 |
| ubot2 | Ubuntu bug 461062 in linux "0x11d41981 on 0x103c30d8 misreports dB information, needs PCM capped at 0 dB" [Undecided,Fix committed] https://launchpad.net/bugs/461062 | 22:58 |
| crimsun | To do this, we need to inspect the reporter's HDA codec, which is attached at http://launchpadlibrarian.net/34413094/Card0.Codecs.codec.0.txt | 22:59 |
| crimsun | So, I'll walk through doing this from the top. | 23:00 |
| crimsun | Firstly, we need to know which codec patch to modify. That information is given at the beginning of the codec information, so, Analog Devices AD1981 | 23:00 |
| crimsun | When you've triaged enough bugs, you no longer look at the ^Codec line but at the ^Vendor Id line | 23:01 |
| crimsun | So, knowing that it's an Analog Devices HDA codec, we'll need to look at sound/pci/hda/patch_analog.c | 23:01 |
| crimsun | Next, we look at the ^Vendor Id line and match it with the entry in the snd_hda_preset_analog[] struct | 23:03 |
| crimsun | (which is located toward the end of the file) | 23:03 |
| crimsun | { .id = 0x11d41981, .name = "AD1981", .patch = patch_ad1981 }, | 23:03 |
| crimsun | so, now we know which function to inspect (patch_ad1981()) | 23:04 |
| crimsun | We need one more piece of information: whether the reporter's hardware is using a specific model quirk. | 23:04 |
| crimsun | To do that, we look at the ^Subsystem Id in the codec output | 23:05 |
| crimsun | In this case, it's 0x103c30d8 | 23:05 |
| crimsun | Now, in patch_ad1981(), ad1981_cfg_tbl[] is used to see if any quirks are necessary | 23:06 |
| crimsun | So we scroll up in the source file to it, and we see that there's a vendor mask already applied: | 23:07 |
| crimsun | SND_PCI_QUIRK_VENDOR(0x103c, "HP nx", AD1981_HP), | 23:07 |
| crimsun | This tells us that we need to look at the AD1981_HP model quirk in patch_ad1981() | 23:07 |
| crimsun | So we return to patch_ad1981() and look at the section for that model. | 23:07 |
| crimsun | Sure enough, there's no existing cap being set for that model. | 23:08 |
| crimsun | Next, we verify our finding again by looking at the codec output | 23:08 |
| crimsun | To do this, we need to look a bit more closely at the pin routing. So, back to the source file, where we look for the mixer setup for the AD1981_HP model quirk | 23:10 |
| crimsun | mixer setups are of type struct snd_kcontrol_new | 23:10 |
| crimsun | so we're looking at ad1981_hp_mixers[] | 23:11 |
| crimsun | Next, find the PCM Playback elements | 23:11 |
| crimsun | The brief version, without referring to the AD1981 data sheet, is that we're looking at the 0x11 node id | 23:11 |
| crimsun | So, go back to the codec output and look at Node 0x11 | 23:12 |
| crimsun | The critical piece of information is in: | 23:13 |
| crimsun | Amp-Out caps: ofs=0x17, nsteps=0x1f, | 23:13 |
| crimsun | so, we need to override the amp setup by using snd_hda_override_amp_caps() | 23:13 |
| crimsun | note that 0x1f will give distortion over and beyond 0x17 | 23:14 |
| crimsun | so we need to cap the nsteps at the offset value | 23:14 |
| crimsun | (the offset value is known as 0 dB) | 23:14 |
| crimsun | so, this function ends up looking like: | 23:15 |
| crimsun | snd_hda_override_amp_caps(codec, 0x11, HDA_INPUT, | 23:15 |
| crimsun | (0x17 << AC_AMPCAP_OFFSET_SHIFT) | | 23:15 |
| crimsun | (0x17 << AC_AMPCAP_NUM_STEPS_SHIFT) | | 23:15 |
| crimsun | (0x05 << AC_AMPCAP_STEP_SIZE_SHIFT) | | 23:15 |
| crimsun | (1 << AC_AMPCAP_MUTE_SHIFT)); | 23:15 |
| crimsun | so we take this addition, put it in the AD1981_HP case of patch_ad1981(), commit the change, and so on. | 23:16 |
| crimsun | (to complicate things, you can also do this from alsactl init, but that's a story for another day) | 23:16 |
| crimsun | For the sake of time, I'm going to skip the powerdown stuff and just send an e-mail to ubuntu-devel@ . | 23:17 |
| crimsun | Anyhow, that's it. | 23:17 |
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