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@@ -97,3 +97,25 @@ $ echo 0 > /sys/bus/intel_th/devices/0-msc0/active
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# and now you can collect the trace from the device node:
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$ cat /dev/intel_th0/msc0 > my_stp_trace
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+
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+Host Debugger Mode
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+==================
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+
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+It is possible to configure the Trace Hub and control its trace
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+capture from a remote debug host, which should be connected via one of
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+the hardware debugging interfaces, which will then be used to both
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+control Intel Trace Hub and transfer its trace data to the debug host.
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+
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+The driver needs to be told that such an arrangement is taking place
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+so that it does not touch any capture/port configuration and avoids
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+conflicting with the debug host's configuration accesses. The only
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+activity that the driver will perform in this mode is collecting
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+software traces to the Software Trace Hub (an stm class device). The
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+user is still responsible for setting up adequate master/channel
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+mappings that the decoder on the receiving end would recognize.
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+
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+In order to enable the host mode, set the 'host_mode' parameter of the
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+'intel_th' kernel module to 'y'. None of the virtual output devices
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+will show up on the intel_th bus. Also, trace configuration and
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+capture controlling attribute groups of the 'gth' device will not be
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+exposed. The 'sth' device will operate as usual.
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Alexander Shishkin