src/gallium/docs/source/debugging.rst

   1 Debugging
   2 =========
   3
   4 Debugging utilities in gallium.
   5
   6 Debug Variables
   7 ^^^^^^^^^^^^^^^
   8
   9 All drivers respond to a set of common debug environment variables, as well as
  10 some driver-specific variables. Set them as normal environment variables for
  11 the platform or operating system you are running. For example, for Linux this
  12 can be done by typing "export var=value" into a console and then running the
  13 program from that console.
  14
  15 Common
  16 """"""
  17
  18 .. envvar:: GALLIUM_PRINT_OPTIONS <bool> (false)
  19
  20 This option controls if the debug variables should be printed to stderr. This
  21 is probably the most useful variable, since it allows you to find which
  22 variables a driver uses.
  23
  24 .. envvar:: GALLIUM_GALAHAD <bool> (false)
  25
  26 Controls if the :ref:`galahad` sanity checker module should be used.
  27
  28 .. envvar:: GALLIUM_RBUG <bool> (false)
  29
  30 Controls if the :ref:`rbug` should be used.
  31
  32 .. envvar:: GALLIUM_TRACE <string> ("")
  33
  34 If set, this variable will cause the :ref:`Trace` output to be written to the
  35 specified file. Paths may be relative or absolute; relative paths are relative
  36 to the working directory.  For example, setting it to "trace.xml" will cause
  37 the trace to be written to a file of the same name in the working directory.
  38
  39 .. envvar:: GALLIUM_DUMP_CPU <bool> (false)
  40
  41 Dump information about the current CPU that the driver is running on.
  42
  43 .. envvar:: TGSI_PRINT_SANITY <bool> (false)
  44
  45 Gallium has a built-in shader sanity checker.  This option controls whether
  46 the shader sanity checker prints its warnings and errors to stderr.
  47
  48 .. envvar:: DRAW_USE_LLVM <bool> (false)
  49
  50 Whether the :ref:`Draw` module will attempt to use LLVM for vertex and geometry shaders.
  51
  52
  53 State tracker-specific
  54 """"""""""""""""""""""
  55
  56 .. envvar:: ST_DEBUG <flags> (0x0)
  57
  58 Debug :ref:`flags` for the GL state tracker.
  59
  60
  61 Driver-specific
  62 """""""""""""""
  63
  64 .. envvar:: I915_DEBUG <flags> (0x0)
  65
  66 Debug :ref:`flags` for the i915 driver.
  67
  68 .. envvar:: I915_NO_HW <bool> (false)
  69
  70 Stop the i915 driver from submitting commands to the hardware.
  71
  72 .. envvar:: I915_DUMP_CMD <bool> (false)
  73
  74 Dump all commands going to the hardware.
  75
  76 .. envvar:: LP_DEBUG <flags> (0x0)
  77
  78 Debug :ref:`flags` for the llvmpipe driver.
  79
  80 .. envvar:: LP_NUM_THREADS <int> (number of CPUs)
  81
  82 Number of threads that the llvmpipe driver should use.
  83
  84
  85 .. _flags:
  86
  87 Flags
  88 """""
  89
  90 The variables of type "flags" all take a string with comma-separated flags to
  91 enable different debugging for different parts of the drivers or state
  92 tracker. If set to "help", the driver will print a list of flags which the
  93 variable accepts. Order does not matter.
  94
  95
  96 .. _rbug:
  97
  98 Remote Debugger
  99 ^^^^^^^^^^^^^^^
 100
 101 The remote debugger, commonly known as rbug, allows for runtime inspections of
 102 :ref:`Context`, :ref:`Screen`, :ref:`Resource` and :ref:`Shader` objects; and
 103 pausing and stepping of :ref:`Draw` calls. Is used with rbug-gui which is
 104 hosted outside of the main mesa repository. rbug is can be used over a network
 105 connection, so the debugger does not need to be on the same machine.