Merge pull request #320 from kanoi/mmq

update FPGA-README for MMQ

FPGA-README

@@ -8,13 +8,19 @@ ModMinerQuad (MMQ)
 The mining bitstream does not survive a power cycle, so cgminer will upload
 it, if it needs to, before it starts mining
 
+-
+
 You must make sure you have an approriate firmware in your MMQ
 Read here for official details of changing the firmware:
  http://wiki.btcfpga.com/index.php?title=Firmware
 
 The basics of changing the firmware are:
+ You need two short pieces of conductive wire if your MMQ doesn't have
+ buttons on the "RESET" and "ISP" pads on the backplane board
+ Cutting a small (metal) paper-clip in half works well for this
+
  Join the 2 left pads of the "RESET" pad with wire and the led will dim
- Without dicsonnecting the "RESET", join the 2 left pads of the "ISP" pad
+ Without disconnecting the "RESET", join the 2 left pads of the "ISP" pad
  with a wire and it will stay dim
  Release "RESET" then release "ISP" and is should still be dim
  Unplug the USB and when you plug it back in it will show up as a mass
@@ -41,6 +47,30 @@ The current latest different firmware are:
 The code is currently tested on the modminer091012.bin firmware.
 This comment will be updated when others have been tested
 
+-
+
+On many linux distributions there is an app called modem-manager that
+may cause problems when it is enabled, due to opening the MMQ device
+and writing to it
+
+The problem will typically present itself by the flashing led on the
+backplane going out (no longer flashing) and it takes a power cycle to
+re-enable the MMQ firmware - which then can lead to the problem happening
+again
+
+You can either disable/uninstall modem-manager if you don't need it or:
+a (hack) solution to this is to blacklist the MMQ USB device in
+/lib/udev/rules.d/77-mm-usb-device-blacklist.rules
+
+Adding 2 lines like this (just above APC) should help
+# MMQ
+ATTRS{idVendor}=="ifc9", ATTRS{idProduct}=="0003", ENV{ID_MM_DEVICE_IGNORE}="1"
+
+The change will be lost and need to be re-done, next time you update the
+modem-manager software
+
+TODO: check that all MMQ's have the same product ID
+
 
 Bitforce (BFL)
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