Motherboard Elite Group A740GM-M v7.0 with IXP700 AHCI controller will time out attempting to query SATA drives in any BIOS configuration while installing 10.3-STABLE. Disabling MSI on the ahci driver via the loader "set hint.ahci.X.msi=0" where X is the ahci bus number, will allow normal detection and access to the SATA disks.
Steps to reproduce
Attempt to install FreeBSD 10.3-STABLE onto a A740GM-M v7.0 motherboard with SATA disk(s).
Boot messages show many timeouts on the ahci bus while querying the disks. During installation and use of the live file system, no SATA devices are available.
Booting into the installation should detect SATA disks as normal. The ahci driver should detect the IXP700 chipset as being unable to use MSI and disable it.
Build date and hardware
FreeBSD 10.3-RELEASE 2016-03-25 usb stick image on amd64
I believe this is also the case with any version of FreeBSD since 8.4-STABLE.
The workaround is to set hint.ahci.0.msi=0 at the loader prompt prior to booting the installation disk.
PR 174985 seems to be related to this issue.