Thinkpads Forum

Hi all - no definitive answer on the web as far as I can see. If I get a DisplayPort - to - HDMI adapter for my T500, will it pass audio as well as video?

I see plenty of "yes" answers for T510 and later, but not for the T500. Thanks.

It won't.

To expound on this, the Motevina chipset doesn't support audio through DP. The workaround I did to connect my T500 to my home theater system was to run my DP-HDMI adapter directly to my TV, then a headphone to RCA adapter to my receiver and hooked into an unused audio port(say, a tape or CD player source). Worked fine, although you obviously only get 2-channel audio.

LegendaryKA8 wrote:To expound on this, the Motevina chipset doesn't support audio through DP. The workaround I did to connect my T500 to my home theater system was to run my DP-HDMI adapter directly to my TV, then a headphone to RCA adapter to my receiver and hooked into an unused audio port(say, a tape or CD player source). Worked fine, although you obviously only get 2-channel audio.

This is basically how mine is hooked up to the TV as well. My TV has one HDMI input that is for computers that has a separate audio in. You can also use a dock then you get SPDIF audio.

Thanks all. I received my DP-to-HDMI adapter and long HDMI cable, and it passes video just fine; but as you confirmed, no audio. I'll try the separate audio cable idea.

LegendaryKA8 wrote:To expound on this, the Motevina chipset doesn't support audio through DP.

This is true. However, W500 also has an ATI Radeon chip which - in combination with the DP article on ThinkWiki - could suggest that audio through DP is in fact possible.

There was never a definitive, competent answer on the subject so I decided to order a DP->HDMI converter and test it under Linux with latest kernel and OpenSource drivers.


My observations:
- DisplayPort video does not work when Intel is the only card (switchable graphics setting not tested)
- DisplayPort does work when Radeon card is the only active video card in Bios. From the first boot screen, the output is on both LCD and DisplayPort monitor
- I was unable to get audio to work. The only Audio devices being detected remain Intel and SPDIF. No ATI audio at all.

Even adding 'radeon.audio=1' to kernel parameters makes no difference.


My conclusion are:

➊ Either:
- the ATI chip in T500/W500 does support audio, but Lenovo didn't bother connecting it physically so it is as if didn't exist.
- this ATI chip has no audio support at all
Either way, there is no physical way to get audio output from DisplayPort on *500 models, even with Radeon cards.


➋ Lenovo advertised DisplayPort in those models as a complete and superior replacement for HDMI, but then screwed their customers over because of incompetence. When it was no longer deniable or defendable, Lenovo entered the intelectually dishonest douchebag mode, as can be witnessed in the last two comments of Mark_Lenovo here: https://forums.lenovo.com/t5/W-Series-T ... 75/page/23


➌ The ThinkWiki http://www.thinkwiki.org/wiki/DisplayPort is misleading on the following account which, after all these years, should finally be corrected:

Audio over DisplayPort when used in conjunction with a DisplayPort to HDMI conversion cable is confirmed to work on W500, T410 and T510 both on integrated and discrete graphics options

I submit that no-one ever tested it on W500, plus - the referenced link mentions nothing of T500/W500.

Lockheed wrote:The ThinkWiki http://www.thinkwiki.org/wiki/DisplayPort is misleading on the following account which, after all these years, should finally be corrected

Done.

In theory it should because it's possible but I wouldn't bet on it that it would work. Display Port is an open source display technology and HDMI is a protected digital adapter through encryption. If it was an analog source and not digital, I think it would work.

https://forums.lenovo.com/t5/W-Series-T ... 75/page/23
Final statement:
"The official position from engineering and development is that there will be no action taken on this series of systems to provide audio on display port."

What's odd is Lenovo rep said no laptop of that generation can do it but I've seen some claims that people have done it with Dell laptops with the same (PM45) chipset (Latitude E6500 / Precision M4400). The W500/W700/T500(discrete graphics) all seem to also use PM45. Also the W700 uses nVidia graphics so it doesn't seem to be only an ATi or Intel graphics issue either if it doesn't work there.
One thread on Dell's forum indicated audio worked with Dell's video driver but not with nVidia generic drivers. Another mentioned something similar regarding the audio driver.