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Diffstat (limited to 'Documentation/trace')
| -rw-r--r-- | Documentation/trace/intel_th.txt | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/trace/intel_th.txt b/Documentation/trace/intel_th.txt index f7fc5ba5df8d..f92070e7dde0 100644 --- a/Documentation/trace/intel_th.txt +++ b/Documentation/trace/intel_th.txt @@ -97,3 +97,25 @@ $ echo 0 > /sys/bus/intel_th/devices/0-msc0/active # and now you can collect the trace from the device node: $ cat /dev/intel_th0/msc0 > my_stp_trace + +Host Debugger Mode +================== + +It is possible to configure the Trace Hub and control its trace +capture from a remote debug host, which should be connected via one of +the hardware debugging interfaces, which will then be used to both +control Intel Trace Hub and transfer its trace data to the debug host. + +The driver needs to be told that such an arrangement is taking place +so that it does not touch any capture/port configuration and avoids +conflicting with the debug host's configuration accesses. The only +activity that the driver will perform in this mode is collecting +software traces to the Software Trace Hub (an stm class device). The +user is still responsible for setting up adequate master/channel +mappings that the decoder on the receiving end would recognize. + +In order to enable the host mode, set the 'host_mode' parameter of the +'intel_th' kernel module to 'y'. None of the virtual output devices +will show up on the intel_th bus. Also, trace configuration and +capture controlling attribute groups of the 'gth' device will not be +exposed. The 'sth' device will operate as usual. |