[Farthom]

Hey all,

I saved up and spent a bunch of money to put together a nice Kodi setup. Unfortunately, I was not able to get things working properly. Usually Kodi is very good about working out of the box.....
When using HDMI audio output, audio works, but is distorted and echoed. (Sounds a bit like a feedback loop when you put two cell phones on speakerphone next to each other...)

My Hardware:
HIS Radeon 280x video card
MSI Z87-GD65 mainboard

Notes
- Only the GUI sounds are distorted.... once playback begins, things seem to go to normal. Both bitstreamed, and decoded audio seem to work.
- Onboard sound card audio works fine, but I really need it over HDMI.
- Using the speaker-test utility to test the speakers results in the same distortions.
- Using KODI in live CD mode, the issue occurs.


Stuff I've Tried
- Disabled onboard audio, no luck.
- Swapped video cards. Also tried a MSI Radeon 7990, a 6870, and a 7970. All video cards had the same audio problem.
- Tried three different HDMI displays supporting audio, all three displays had the same issue.
- Grabed the official Ubuntu 14.04 distro (non KODI) same issue occurs. Also tried the 15.x non LTS Ubuntu, same issue.
- Tried inserting "options snd-hda-intel vid=8086 pid=8ca0 snoop=0" as per this article: http://askubuntu.com/questions/405071/st...hdmi-audio


I tracked down this kernel bug (http://www.spinics.net/lists/dri-devel/msg85506.html) Which seems to accurately describe my situation. It seems to be unresolved, and I cant seem to find any working workarounds.
Any advice? This seems like a pretty serious issue affecting anyone trying to use AMD cards....

Thanks in advance!

[fritsch]

What you can try is: Update the kernel to 4.1.2 - besides that - no chance, sorry. As you found out - severe kernel bug.

Concerning workarounds: Some said, that using pulseaudio which opens the ALSA driver differently improved the situation. But kodi uses pulse by default if installed - and as I did not see the Debug Log - not sure if you already run that.

[Farthom]

I am not running pulse, and unfortunately since my sound system is on the nicer side, I am too stubborn to give up bitstreaming for it. I'll look into upgrading the kernel, however I figure it will be a very difficult involved process on ubuntu....

Thanks for the reply, having a a dev confirmation of a bug makes me feel a little bit better about being unable to figure it out. I'll see where I get with an ungraded kernel, but I figure I'll end up settling on the windows version of Kodi for the time being, until some of these fixes trickle down the vines into a Ubuntu LTS/Kodi distro. Windows makes me feel a bit unclean, but at least it should work.

[fritsch]

How about not using an AMD gpu anymore? GT610 or GT720 will solve that issue immediately?

You could also try the latest OpenELEC beta and see if that works - if yes, we can do something against it on your installation.

[Farthom]

I tried OpenELEC actually, and sadly I couldn't even get the installer to run. I would choose "3 - Install OpenELEC" and the installer would just flash an error about being unable to open some file in /tmp and crash. I'm reasonably certain the preinstall environment kernel does not support my SATA storage device. I have encountered this issue before with other linux, where I need to use the newest of new versions to avoid it. The usual error would be something like, cant mount cd, or cant find any hard drives etc. Looks like this hardware is cursed in more ways than one hehe. The ELEC version I tried was the 5.95.2 BETA. I am grabbing the stable nonbeta, in the off chance this install issue is something else. I'll also see if I can get a build off the raw git source, as it *appears* (I'm no expert) they just added kernel 4.1.2 as of yesterday.

As for an Nvidia card..... yeah, I wish. It would solve everything. The reason I am using AMD, is because I'm one of those idiots who mined bitcoins.... I have 20+ high end AMD graphics cards, along with a pile of the above listed motherboard. So the money I "saved up" to build this, was really just for a nice HTPC case and a few odds and ends. I could 3 way SLI three 7990 cards if I wanted! However I want a KODI setup not a second oven. As cool as that would be hehe.

[fritsch]

As for an Nvidia card..... yeah, I wish. It would solve everything. The reason I am using AMD, is because I'm one of those idiots who mined bitcoins.... I have 20+ high end AMD graphics cards, along with a pile of the above listed motherboard. So the money I "saved up" to build this, was really just for a nice HTPC case and a few odds and ends. I could 3 way SLI three 7990 cards if I wanted! However I want a KODI setup not a second oven. As cool as that would be hehe.

Hahaha - that made me laugh :-) But you are an honest guy.

For OpenELEC. Gunzip the img.gz and dd it onto a usb stick. Then enter "live" when it asks you what to do.

[Farthom]

Thanks for that tip! It saved me typing out all the crap I've been doing in an effort to make OpenELEC install to no avail. Live mode boots up nicely! Unfortunately, both the stable version and beta version of ELEC have the audio distortion. Given what we have found out about the kernel bug, I honestly expected this.

The commit linked to a reply in the kernel bug report, (http://git.kernel.org/cgit/linux/kernel/...161080ce5c) appears to have gone in June 25, 2015, and 4.1.2 was released July 10, I feel there is a good chance I will be successful if I can find a way to use the newest hot of the pan kernel somehow. Given how ELEC seems to have moved to 4.1.2 in their git, I figure trying to build that is my best shot at success.

Thanks for all the help so far, unless there anything else you would like me to try, it will likely be many hours delay, while I battle the entirely unknown openELEC build system.

[fritsch]

That's quite easy:

Code:

mkdir kernel
cd kernel
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-rc2-unstable/linux-headers-4.2.0-040200rc2-generic_4.2.0-040200rc2.201507121935_amd64.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-rc2-unstable/linux-headers-4.2.0-040200rc2_4.2.0-040200rc2.201507121935_all.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.2-rc2-unstable/linux-image-4.2.0-040200rc2-generic_4.2.0-040200rc2.201507121935_amd64.deb
sudo dpkg -i *deb

I doubt it's in there: https://www.kernel.org/pub/linux/kernel/...eLog-4.1.2 it only went to git kernel. Therefore I linked you the last rc2.

Edit: This is for your ubuntu

[Farthom]

Gave this a try. I was not aware it was this simple to change kernels..... I expected some serious source compilation, and grub config nonsense. Sadly, it looks like the fix didn't make it into this kernel.

Just to be sure, I checked I was actually running the right kernel with uname -r. It was correct.

As a last resort, I'll try compiling the latest Elec, but I am not very hopeful.

[fritsch]

Here, try the nightly kernels: http://kernel.ubuntu.com/~kernel-ppa/mai...y/current/

just download the headers-generic-64, _all and the generic image-64 as you see above, then install them.

[Robotica]

How about not using an AMD gpu anymore? GT610 or GT720 will solve that issue immediately?

You could also try the latest OpenELEC beta and see if that works - if yes, we can do something against it on your installation.

What happened? I thought you liked AMD hardware, except for their prop. drivers. I thought OSS Radeon drivers really pleased you?

[fritsch]

There are no working drivers for the latest cards ... it's wip, that's the issue ... but as you see I try to help him, but he is a newbie in kernel upgrade regard - a 20 dollar investment would save him a lot of troubles.

[Farthom]

I should add a point, which I've omitted since it's irrelevant to the problem at hand. I'm dual booting windows with the intention of using it as a half Steam box. Thus, moving to Nvidia would require a high end card equivalent to the Radeon 280x. This is an investment of several hundred dollers vs $20.

I've kind of settled with using Kodi alongside Steam on the windows side. I'm actually more pleased with it than expected, all the issues which made me move over to linux appear to be fixed. I wrote up a quick shitty explorer.exe shell replacement to allow switching between Kodi and Steam seamlessly. The end result, a pretty nice setup.

I didn't delete the Ubuntu partition however, and I will give the nightly kernel a try tonight. Even though I've settled, I figure I can't be the only one on the planet who wanted to use an AMD card, so for the sake of anyone else attempting AMD I'll take half an hour to try this out and report.

[Robotica]

There are no working drivers for the latest cards ... it's wip, that's the issue ... but as you see I try to help him, but he is a newbie in kernel upgrade regard - a 20 dollar investment would save him a lot of troubles.

I understand the issue. First, it's a long time waiting between announcement and retail availability and once available drivers are only partly done. Then that needs a few months work to get everything up and running. Obviously, this process is not satisfying for you. I had the feeling this driver mess turned for the better for both Catalyst and OSS Radeon...

Hopefully, AMD will become a better donor to this community so you can continue all your (and Fernetmenta's) effort to the decode and render pipelines. Because I would love to see some better competition to Intel to compete their next HTPC hit, $135 Braswell Chromebox-alike OS-free full systems.

[AndyFurniss]

FWIW rather than trying new kernels, you can probably infer whether your audio pciid is in by looking at the name of the alsa device - if it's Generic it isn't in.

I also doubt that it will make any difference either way :-(

This is a strange bug, it seems you need the "right kind of cpu load" - I also just managed to reproduce with fglrx on clean install of Ubuntu 15.04.

Workarounds are easy for me - just use s/w decode for HD TV. SD TV needs more - not sure what to do with kodi. with mpv I just force a pointless s/w 420 - 422 conversion to get enough load.