Megaraid driver bug?

[PCnity]

Hello

I installed fresh Gentoo to a Supermicro server with PERC4/DC scsi raid controller, but it wont boot. I looks like a kernel bug related to the megaraid driver.
After booting Gentoo live cd or any other installation media which uses initrd, everything works ok. System finds all internal devices and also arrays attached to the controller. So if i install ubuntu or debian, system boots ok... But if i install Gentoo with my own kernel with megaraid compiled in the booting process stucks at "megaraid: probing new devices" and freezes... If i compile it as a module... I can load megaraid_mm.ko ok but after modprobe megaraid_mbox.ko it stucks... dmesg does not show anything...

I tryed everything to work it out (genkernel, mkinitrd) but i can not boot to a system where everything works... I should be a XEN machine so i tryed to install debian lenny and use their xen system... It uses initrd but stucks at the same point.

By many eperiments with debian i found out that it depends on the time of loading the module... When i changed the modules.order file and updated the initrd, the megariad drivers was included successfully, BUT the system was stuck on ide0...

All this happens on only amd64 (SMP)... On i386 (SMP) is everything ok. I can compile the megariad in kernel and it works.

I am not advanced user enough to know where to look at now... All this is replicable on any 64 bit kernel and megaraid card. On gentoo-sources (2.6.28 and 2.6.29) and also xen-sources.

Can anybody tell me a suggestion why gentoo livecd boots ok and i see all disk drivers (internal + SCSI) and why compiled kernel with all drivers needed not? Thak you for all help.