Weird PC Speaker behavior on HP ProBook 6540b

[Blue Beret]

Hi, I've got an HP ProBook 6540b WD685EA running Debian unstable, kernel 2.6.32-5-amd64. The PC Speaker worked fine under the kernel from lenny (2.6.26) but now it shows some sort of weird behavior: it plays all beeps with considerably lower frequency (a few octaves, even when using the 'beep' utility with specified frequency) and crackles on reboot (probably a very-low frequency sound, this freaked me out the first time I heard it, sounded like the laptop was breaking apart).
Interestingly, the 'pcspkr' module isn't shown in lsmod, and when I insert it manually, the speaker stops working ('beep' waits but nothing is heard).
I tried playing with the PC Speaker channel in AlsaMixer, but that didn't help. Any more ideas?

[Blue Beret]

Okay, now I've found that the 'pcspkr' module enables the volume setting in ALSA, where I can mute the speaker, yet the speaker still beeps even if the module is unloaded. Re-loading the module causes a new device to be created, which explains why it goes mute.

Still, no matter whether the module is loaded or not, the speaker still beeps strangely low in pitch unless muted. The difference is something between 2 and 3 octaves.

[bla123]

same crackling sound when rebooting or shutting down over here.
Did upgrade to kernel 2.6.32-22, but problem remains
HP ProBook 6540b with ubuntu 10.04... Still not sure how to get around this one