A method for computing includes submitting a first command from a central processing unit (CPU) to a first peripheral device in a computer to write data in a first bus transaction over a peripheral component bus in the computer to a second peripheral device in the computer. A second command is submitted from the CPU to one of the first and second peripheral devices to execute a second bus transaction, subsequent to the first bus transaction, that will flush the data from the peripheral component bus to the second peripheral device. The first and second bus transactions are executed in response to the first and second commands. Following completion of the second bus transaction, the second peripheral device processes the written data in.