Bug 22088

Summary: GM45 chipset sends audio signal through DisplayPort
Product: xorg Reporter: ingvar <then00b183>
Component: Driver/intelAssignee: Wu Fengguang <wfg>
Status: RESOLVED FIXED QA Contact: Xorg Project Team <xorg-team>
Severity: minor    
Priority: low    
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
dump intel audio related registers as well as a hack to disable audio output
none
dump intel audio related registers as well as a hack to disable audio output none

Description ingvar 2009-06-04 11:12:12 UTC 
I got Lenovo T500 with Intel GM45 chipset and I tried to connect it with TV through DisplayPort (DP -> DVI -> HDMI). Since this chipset doesn't support audio over DisplayPort (and I got DVI adapter between), I plugged analog audio to computers headphone out.

The problem is that TV doesn't read analog audio signal since it recives some dummy audio signal through HDMI (and I don't have any options to change this).

Driver version before 2.6 works, so I read changelog and found this commit http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/?id=42b3903c3fda95a7c536cb957d8163d8dc54a9a1 
I uncomment it and compiled. Then sound works on TV.

Since T500 with this chipset doesn't support audio through DisplayPort, this option might be removed?
Comment 1 Wu Fengguang 2009-06-04 19:31:21 UTC 
Created attachment 26449 [details] [review]
dump intel audio related registers as well as a hack to disable audio output

1) apply this patch to latest xf86-video-intel git tree
2) cd src/reg_dumper; make intel_audio
3) ./intel_audio # run this after startx
4) the audio output should be disabled now
Comment 2 Wu Fengguang 2009-06-04 19:36:19 UTC 
Created attachment 26450 [details] [review]
dump intel audio related registers as well as a hack to disable audio output

1) apply this patch to latest xf86-video-intel git tree
2) cd src/reg_dumper; make intel_audio
3) ./intel_audio # run this after startx
4) the audio output should be disabled now
Comment 3 ingvar 2009-06-05 09:25:18 UTC 
It works:)
Thank you!
Comment 4 Wu Fengguang 2009-06-05 17:13:12 UTC 
On Fri, Jun 05, 2009 at 09:25:19AM -0700, bugzilla-daemon@freedesktop.org wrote:
> http://bugs.freedesktop.org/show_bug.cgi?id=22088
> 
> 
> ingvar <then00b183@gmail.com> changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>              Status|NEW                         |RESOLVED
>          Resolution|                            |FIXED
> 
> 
> 
> 
> --- Comment #3 from ingvar <then00b183@gmail.com>  2009-06-05 09:25:18 PST ---
> It works:)
> Thank you!

Thanks for the feedback. So I'll release that utility some time later,
with some options to enable/disable audio outputs :)

Maybe it's also possible to disable audio output automatically for
DisplayPort on GM45, but that could take much more time to happen.

Thanks,
Fengguang

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