Ubuntu 12.04: Suspend/resume needs manual invocation of acpi_fakekey

I have been having intermittent suspend/resume problems with my laptop (Toshiba Satellite L505), previously with 10.04 and now with 12.04.

In the latter case, after two consecutive fresh installs of Ubuntu 12.04, suspend/resume initially worked fine. In both cases it stopped working after some unknown event. The behaviour was that upon closing the lid the computer would suspend, but upon reopening it I would get a black screen with the backlight blinking on and off. Trying Crtl-Alt-Backspace, Crtl-Alt-F1 etc would not fix this. Only a hard reboot (or a Alt-Prtsc-REISUB) would get me a new session.

I tried several tests to ascertain the source of the malfunction:
-I tried removing the packages I had installed after the latest known stable state of my system (using kernel 3.5.0-37): NOTHING
-I tried dist-upgrading the kernel (to 3.5.0-39): NOTHING
-I even tried with a kernel I had compiled for my own CPU (from 3.5.7-16): NOTHING
So, not a kernel problem.

Then, taking inspiration from this solution: http://askubuntu.com/questions/9518/ubuntu-wont-suspend-anymore-but-it-did-upon-install/10579#10579"]
I checked to see if I have acpi-support installed on my system. I did.
Moreover, I observed on the Software Center description page that: "This program is run from acpi_fakekey"

So, I opened a terminal, issued:
acpi_fakekey
and closed my lid. Then I opened it again and... SUCCESS! My session resumed!
Then I closed my lid again and... NO RESUME!

Then I made several tests with all three different kernel versions. The results: each time I issued
acpi_fakekey
BEFORE closing the lid I could suspend/resume. If I didn't, I got a blinking black screen and needed to Alt-Prtsc-REISUB.

So, I suspect that the acpi_fakekey command needs to be inserted at the beginning of the suspend sequence, and/or at the end of the resume sequence.

Can anyone else reproduce this bahaviour? Is this a bug?