I've got a PCI SATA (4xport) card with Sil3114 and hot swappable mobile rack.
SATA drives work great, but when I trying to chahnge them - I have to
echo "scsi remove-single-device 0 0 0 0" > /proc/scsi/scsi
then replace hard drive connect it back and
echo "scsi add-single-device 0 0 0 0" > /proc/scsi/scsi
Seems to work ok. But only if using same capacity hard drive,
when I've put a different hard drice (for ex was 200GB then I've put 120gb) it will still show size and geomtery for old hard drive.
The only way I found is to compile kernel with sata_sil as module and then
rmmod sata_sil
modprobe sata_sil
to recognise a new hard drive properply. But if I use all 4 ports then it sholud be some other way to tell kernel (module) that I put a new hard drive and it needed to register it.

How I can do it?
Is it any way to ask kernel(module) to rescan it?

I'm not sure the kernel supports SATA hotswap, but have you simply tried rescanning the partition using sfdisk?

You can try to use `hdparm -z`.

No after reread partition using sfdisk or hdparm will show a new partition but still old HDD geometry and old HDD size