[alsa-devel] NVIDIA HDMI surround sound is broken starting with kernel 2.6.36
user.vdr at gmail.com
Mon Jan 31 19:37:05 CET 2011
On Mon, Jan 31, 2011 at 9:51 AM, Stephen Warren <swarren at nvidia.com> wrote:
>> Also, even though the eld file is removed, the eld info is _not_
>> updated when stopping alsa & unloading drivers, then reloading. A
>> reboot is required to get the eld info to update. This is why I cold
>> boot the pc for each test.
> The NVIDIA graphics driver reads the monitor's EDID and passed the ELD
> information to the audio HW, from whence it is read by the ALSA driver.
> The EDID is only read when the X server is started, or perhaps when you
> click the "detect displays" button in the nvidia-settings utility.
> Hence, restarting X (e.g. logout/login), or using nvidia-settings, is
> probably sufficient to update the ELD data; no reboot required.
That explains why the ELD info isn't updated, although doesn't explain
the actual problem of missing channels. I do think it's worthy to
rethink that behavior in the Nvidia driver. The reason being that
many users, like myself, are using an htpc environment where the
audio/video output is connected directly to a tv or home theater
receiver. In my case it's a receiver that is turned on/off as needed.
There is no keyboard, mouse, or anything other then an IR remote
control to navigate the software I'm running. To click "detect
displays" would mean digging the box out of its current location and
connecting a monitor & mouse to it just to do so. Extremely
inconvenient. I would guess that the best solution would be the
Nvidia driver having the ability to update the ELD info upon request.
There's got to be method of detecting things like receivers being
Maybe another thread should be started regarding that issue since
we're getting away from the problem of missing channels.
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