annotate rvinterf/README @ 273:d6dfad22cccd

doc/RVTMUX: note about fc-tmsh ffs2 commands being a known dead end
author Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
date Fri, 07 Feb 2014 07:33:29 +0000
parents f42854da4563
children f114f5c547ec
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f42854da4563 rvinterf: beginning of refactoring
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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1 I (Spacefalcon the Outlaw, FreeCalypso developer) am still learning what kinds
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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2 of traffic may be passed across TI's RVTMUX binary-packet serial interface. We
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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3 already know that much of this traffic is debug trace output, i.e.,
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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4 unidirectional and essentially unconditional output from the GSM device. All
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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5 of the "standard" firmwares we have (mokoN, our leo2moko which functions almost
f42854da4563 rvinterf: beginning of refactoring
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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6 identically, and Pirelli's fw) produce massive volumes of such trace output in
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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7 normal operation. We already know that this "unsolicited" trace output comes
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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8 in at least 3 different flavors:
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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9
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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10 * RiViera traces emitted by rvf_send_trace()
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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11 * L1 traces
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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12 * G23 traces
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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13
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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14 The RVTMUX interface can be used for more than just trace output, though: any
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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15 component in TI's fw suite can send and/or register to receive binary packets.
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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16 As I slowly work my way through various components which comprise TI's Leonardo
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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17 fw whose semi-source we use as our reference version, learning what they do and
f42854da4563 rvinterf: beginning of refactoring
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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18 reintegrating them in our own gsm-fw, I will undoubtedly uncover additional uses
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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19 to which the RVTMUX interface is put.
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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20
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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21 Aside from the trivial provision in the RVT module itself whereby an external
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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22 host can send a command to the target to set a filter masking some of the RV
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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23 trace output, so far the only entity I've come across which accepts packets from
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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24 an external host is ETM (Enhanced Test Mode). ETM implements a registration
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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25 system of its own, whereby other modules can register with ETM to receive
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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26 certain external command messages passing first through RVT, then through ETM.
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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27
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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28 Because I do not yet have a clear mental picture of *every* function for which
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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29 the RVTMUX interface will ever be used, it is correspondingly impractical to
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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30 decide on a once-and-for-all design of what the host-side software for talking
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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31 to this interface should be like. Therefore, it is currently premature to
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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32 expect any stability in the present rvinterf subdirectory of freecalypso-sw; I
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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33 may implement something one day, then toss it away the next day (without
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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34 providing much in the way of backward compatibility) when I come up with some
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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35 other idea.
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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36
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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37 The current roadmap for what the rvinterf suite of host tools is envisioned to
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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38 look like eventually is as follows:
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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39
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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40 rvtdump Opens the serial port, decodes TI's binary packet protocol, and
f42854da4563 rvinterf: beginning of refactoring
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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41 simply dumps every received/decoded packet on stdout in a human-
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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42 readable form. No provision for sending anything to the target.
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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43 Intended use: observing the debug trace output which all TI
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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44 firmwares emit as standard "background noise". This utility has
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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45 already been written, and it allows one to observe/log/study the
f42854da4563 rvinterf: beginning of refactoring
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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46 "noise" that appears on Pirelli's USB-serial port (running
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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47 Pirelli's original fw), as well as that emitted on the IrDA
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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48 (headset jack) port on the GTA02 by mokoN/leo2moko firmwares.
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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49
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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50 rvinterf My plan is to make a copy of rvtdump, called rvinterf, and have
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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51 it act very much like rvtdump: receive TI's packets from the
f42854da4563 rvinterf: beginning of refactoring
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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52 serial port, decode them and print the decoded form on stdout.
f42854da4563 rvinterf: beginning of refactoring
Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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53 However, rvinterf will also create a listening UNIX domain
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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54 socket to which other programs in the present suite will
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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55 connect. These other programs connecting through rvinterf will
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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56 be able to send packets to the target, as well as register to
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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57 receive certain kinds of target->host message packets.
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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58
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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59 fc-tmsh FreeCalypso Test Mode Shell is my vision for the utility which
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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60 will provide a practically usable interface to ETM. ETM's
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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61 general mode of operation seems to be (weasel phrase inserted
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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62 because many other fw components may connect through ETM, and I
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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63 have yet to study all of them) command-response: an external
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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64 host sends a command to ETM, that command gets dispatched to the
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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65 proper registered handler, the command function is executed, a
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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66 response packet is composed, and finally that response is sent
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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67 back to the host. But because all code on the target side is
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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68 under active development and debugging, we should not expect
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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69 perfect lock-step behaviour on the interface; instead, our
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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70 fc-tmsh should be fundamentally asynchronous: when the user
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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71 enters a command, the appropriate command packet is sent to the
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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72 target, but we are prepared for target->host messages at any
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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73 time, without enforcing strict correspondence to issued
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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74 commands: let the developer-operator sort that out instead.
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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75
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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76 The usage scenario I envision is that one will need to run rvinterf first
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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77 (either directly or through fc-xram) in one terminal window, leave it running,
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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78 then run fc-tmsh in another terminal window, and have it connect to rvinterf
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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79 via the local UNIX domain socket interface. Why such complexity, why not have
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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80 one program do everything? I suspect that in many debug/experimentation
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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81 sessions it will be necessary to use fc-tmsh on "noisy" targets, i.e., in
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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82 scenarios where the target is continuously spewing its "normal" voluminous debug
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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83 trace output, such that the "interesting" output as in responses to commands
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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84 gets drowned in the noise. In such a scenario it would be helpful to have one
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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85 terminal window in which one sees the transcript of the fc-tmsh session,
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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86 consisting of issued commands and received ETM responses without the general
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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87 noise, and another window in which one sees all RVTMUX interface activity in
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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88 real time - the latter would allow one to observe commands having side effects
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Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
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89 outside of ETM, such as crashing the whole fw. :-)