Speakers are NOT detected as they do NOT need drivers to work.
Drivers for sound are loaded yes but that is all.
It is impossible to have speakers detected as they are just external .
A pc cannot detect whether speakers are connected or not, if that was so
then if headphones were connected and not speakers then headphones would be
detected.
All that happens is the audio card /built in audio drivers get loaded.
A pc cannot know what is connected to speaker jacks.
USB speakers yes, regular ones no.
If I unplug my speakers then the setup for the sound and how the speakers
are configured stay the same.
If you have ever unplugged your speakers and plugged in headphones instead
have you ever seen it change from speakers to headphones on it's own?
No because it is not possible.
Speakers ARE detected. Speaker detection is used for the nifty
feature of auto-configuring the sound chip, so the user doesn't
have to do it manually. For example, if the user plugs in three
sets of speakers, the sound chip senses them, and the driver for
the sound chip, switches to 5.1 mode to drive the speakers. If
the user yanks two of the plugs out, leaving a set of stereo
speakers connected, the software can switch to 2.0 mode with no
user intervention.
I don't know if this is the latest revision any more, but have
a look on page 68 of the AC97 spec:
ftp://download.intel.com/labs/media/audio/download/ac97_r23.pdf
"Sensed bits relates to the I/O being sensed as either output
or inputs.
Sensed bits (outputs).
This field allows for the reporting of the type of output
peripheral/device plugged in the jack. Values specified below
should be interrogated in conjunction with the SR[5:0] and
OR[1:0] bits for accurate reporting.
00h Data not valid.
01h Indicates that there are no connected devices.
02h Fingerprint. Indicates a specific fingerprint value for
devices that are not specified or are unknown.
03h Speakers (8 ohms)
04h Speakers (4 ohms)
05h Powered speakers
06h Stereo headphone
07h SPDIF Out (electrical)
08h SPDIF Out (TOS)
09h Headset (mono speaker left channel and microphone. Read
Functions 5 and 4 for matching Microphone)
0Ah Other. Allows a vendor to report sensing other type of
devices/peripherals. SR[5:0] together with OR[1:0] provide
information regarding the type of device sensed.
0Bh-0Eh Reserved
0Fh Unknown (use fingerprint)
10-1Fh Reserved
OR[1:0] 0h Order Bits
These bits indicate the order the sensed result bits SR[5:0]
are using.
00 10 0 (i.e., Ohms)
01 10 1 (i.e., 10 Ohms)
10 10 2 (i.e., 100 Ohms)
11 10 3 (i.e., 1K Ohms)"
That should give a hint of how it works. The sound chip measures
the impedance of the connected device, and reports what it finds
to the software. A stereo headset, for example, is typically 32ohms
and is different than an unamplified speaker, which could be 8
or 4 ohms (or many other values for that matter). When a measured
value doesn't fall in a neat catagory, the "order bits" indicate
the magnitude of the reading.
In the case of the OP, his problem could be due to an immature
driver, as the notion of always successfully recognizing what
is plugged in, is pretty crazy in my opinion. I hate jack sensing
schemes, when they cannot be disabled, and I have a video card
that does stupid things, when IT decides to. Video cards also
have jack sensing.
Paul
