README.ASIC: Document how to use Monarch in a PCI-Express arrangement on Linux

README.ASIC

@@ -195,6 +195,40 @@ make AR=arm-angstrom-linux-gnueabi-ar
 
 BFGMiner has also been incorporated into an unofficial firmware by uski01 called Bertmod this can be found on the kncminer forum.
 
+
+MONARCH
+-------
+
+The Butterfly Labs Monarch devices can be used as either USB devices, or in a
+PCI-Express slot. As USB devices, they are essentially plug-and-play. If you
+wish to use them via PCI-Express, however, you must first load the proper
+driver. BFGMiner can work with either Linux uio (2.6.23+, requires root access)
+or Linux vfio (3.6+, requires IOMMU support).
+
+To enable uio on your cards, you may need to do:
+    sudo modprobe uio_pci_generic
+    echo 1cf9 0001 | sudo tee /sys/bus/pci/drivers/uio_pci_generic/new_id
+
+Enabling vfio is similar, but more complicated, but allows you to run BFGMiner
+without root privileges. First, load the kernel module and tell it to accept the
+Monarch:
+    sudo modprobe vfio-pci
+    echo 1cf9 0001 | sudo tee /sys/bus/pci/drivers/vfio-pci/new_id
+Next, identify what the device ids are for your card(s):
+    lspci -D | grep 1cf9  # the first number of each line is the device id
+From that, you can identify its IOMMU group, and list all devices sharing that
+group:
+    readlink /sys/bus/pci/devices/<device_id>/iommu_group
+    ls /sys/kernel/iommu_groups/<iommu_group>/devices/
+All of the devices listed (other than the Monarch), if any, will need to be
+disabled and unbound! To do that, use:
+    echo <device_id> | sudo tee /sys/bus/pci/devices/<device_id>/driver/unbind
+If you want to run BFGMiner as a normal user:
+    chown <username> /dev/vfio/<iommu_group>
+Depending on your system, you may also need to do:
+    echo 1 | sudo tee /sys/module/vfio_iommu_type1/parameters/allow_unsafe_interrupts
+
+
 ---
 
 This code is provided entirely free of charge by the programmer in his spare