It seems that code that puts rx1950 into sleep is not clear: even in sleep mode rx1950 consumes some power. After ~8h in sleep ~20% of battery was eaten :(
I suspect one cause of this problem can be sd/mmc card power management - it was not implemented for rx1950. So I implemented rx1950 s3c2410_mmc_def_setpower function that controls sd/mmc card power. When GPJ1 == 0 card is not powered, when GPJ0 == 1 card is powered.
Some info about card-related gpios:
GPJ1 - controls card power (1 == on)
GPH8 - ro sense, (1 == rw, 0 == ro)
GPF5 - card detection
Latest patch is available here
Precompiled kernel and sound modules are available here