Monday, 15 September 2008, 16:20:22 EDT

Speaking of problems with my MythTV machine, I recently lost sound on the machine. I built my HTPC (Home Theatre Personal Computer) to be a High-Definition machine. As such, I intended to have one cable connecting the HTPC to my television — an HDMI cable. I specifically bought a nVidia GeForce 8500GT because it uses passive cooling (no fan noise) and has an SPDIF audio input so that it can pass audio out over an HDMI cable. After putting the machine together, and getting it all setup, I discovered that the nVidia drivers for Linux did not support passing audio over the HDMI cable. So I sighed, maybe said a few choice words in nVidia's direction, and connected an eighth inch DIN to RCA cable between the HTPC and my television. All was dandy!

Fast forward to last Thursday, when I decided to work on my HTPC. The first thing I did was update the operating system and software. That meant I got new video card drivers; version 173 instead of the old version 169. Suddenly I had no sound! Actually, I had much weirder problem. I could play sound at the console, before starting the X session, but got only silence after X had started. It took me a while to discover this, but once I did, it was clear that the video card driver was doing something very strange. After a bit of searching, I came across a single forum post that gave me the answer. In the 173 version of the driver, nVidia had silently enabled audio over HDMI (oh the irony!).

I spent hours trying to get sound to play via the HDMI cable. But for some reason my machine just will not do it (I'm beginning to think the patch cable from the sound card to the video card is bad). So I switched over to a regular VGA connection. I quickly got tired of that. The picture was blurry and I had to restart X multiple times whenever I turned on the television, because the display wasn't syncing properly.

In an effort to get this resolved, I wrote a lengthy post to the forum asking for help. I had not received any replies by lunch this afternoon, so I bought a DVI to HDMI cable to try when I got home. After lunch, however, I found a thread on the forum detailing my same problem along with a fix. So now, thanks to that thread, an older post, and Hex Fiend, I have working sound again.

I'm writing this post just in case someone else is having the same problem, and they are not having any luck finding the resources that took me four days to find.


So you now have sound via HDMI? Pretty sweet. I keep thinking I want to do this because everything I have up front is a tightly locked down appliance.

Posted by Mr Frosti on Friday, 26 September 2008, 15:15:00 EDT.

No. I do not have audio coming over HDMI right now. The video card drivers want to send the audio over HDMI, but it isn't working for me. I have no idea why. The solution was me eliminating the extended EDID information from my television's EDID data. That way, the video card does not think it can send the television audio.

Posted by James Sumners on Friday, 26 September 2008, 16:25:40 EDT.