2.4.22-pre1 X screen blank problem

Just as the RedHat 8.0 kernels do, 2.4.22-pre1 enters the
screen blanking due to inactivity but it doesn't unblank the screen anymore. 2.4.21 doesn't have this problem.
I can type commands and have them executed, but I don't
see what I type (I do this from VCs after switching out of blind-X by Ctrl-Alt-F2 or first available tty anyway).

Dell Latitude C640, Radeon 7500 mobile, A07 bios, ACPI.

Any further info available to interested people :)

Thanks, ciao

--alessandro

"I'm always trying to find some kind of honest emotion
and connection with the most naked human emotions.
It's a dangerous, dark path but also very exciting."
(Steve Wynn, interviewed by 'Mescalina', 2003)