diff --git a/util/dtd_parser/dtd_parser.py b/util/dtd_parser/dtd_parser.py
new file mode 100755
index 0000000000..bbce858a9d
--- /dev/null
+++ b/util/dtd_parser/dtd_parser.py
@@ -0,0 +1,213 @@
+#!/usr/bin/python
+# dtd_parser.py - DTD structure parser
+#
+# Copyright (C) 2012 The ChromiumOS Authors. All rights reserved.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+#
+
+'''
+DTD string parser/generator.
+
+Detailed timing descriptor (DTD) is an 18 byte array describing video mode
+(screen resolution, display properties, etc.) in EDID and used by Intel Option
+ROM. Option ROM can support multiple video modes, specific mode is picked by
+the BIOS through the appropriate Option ROM callback function.
+
+This program allows to interpret the 18 byte hex DTD dump, and/or modify
+certain values and generate a new DTD.
+'''
+
+import sys
+
+#
+# The DTD array format description can be found in
+# http://en.wikipedia.org/wiki/Extended_display_identification_data, (see the
+# EDID Detailed Timing Descriptor section).
+#
+# The below dictionary describes how different DTD parameters are laid out in
+# the array. Note that many parameters span multiple bit fields in the DTD.
+#
+# The keys in the dictionary are stings (field names), the values are tuples
+# of either numbers or tri-tuples. If the element of the tuple is a number, it
+# is the offset in DTD, and the entire byte is used in this field. If the
+# element is a tri-tuple, its components are (DTD offset, bit shift, field
+# width).
+#
+# The partial values are extracted from the DTD fields and concatenated
+# together to form actual parameter value.
+#
+
+dtd_descriptor = {
+ 'dclck' : (1, 0),
+ 'hor_active' : ((4, 4, 4), 2),
+ 'hor_blank' : ((4, 0, 4), 3),
+ 'vert_act' : ((7, 4, 4), 5),
+ 'vert_blank' : ((7, 0, 4), 6),
+ 'hsync_offset' : ((11, 6, 2), 8),
+ 'hsync_pulse_width' : ((11, 4, 2), 9),
+ 'vsync_offset' : ((11, 2, 2), (10, 4, 4)),
+ 'vsync_pulse_width' : ((11, 0, 2), (10, 0, 4)),
+ 'hor_image_size' : ((14, 4, 4), 12),
+ 'vert_image_size' : ((14, 0, 4), 13),
+ 'hor_border' : (15,),
+ 'vert_border' : (16,),
+ 'interlaced' : ((17, 7, 1),),
+ 'reserved' : ((17, 5, 2), (17, 0, 1)),
+ 'digital_separate' : ((17, 3, 2),),
+ 'vert_polarity' : ((17, 2, 1),),
+ 'hor_polarity' : ((17, 1, 1),),
+ }
+
+PREFIX = 'attr_'
+
+class DTD(object):
+ '''An object containing all DTD information.
+
+ The attributes are created dynamically when the input DTD string is
+ parsed. For each element of the above dictionary two attributes are added:
+
+ 'attr_' to hold the actual parameter value
+ 'max_attr_' to hold the maximum allowed value for this parameter.
+ '''
+
+ def __init__(self):
+ for name in dtd_descriptor:
+ setattr(self, PREFIX + name, 0)
+
+ def init(self, sarray):
+ '''Initialize the object with values from a DTD array.
+
+ Inputs:
+
+ sarray: a string, an array of ASCII hex representations of the 18 DTD
+ bytes.
+
+ Raises: implicitly raises ValueError or IndexError exceptions in case
+ the input string has less than 18 elements, or some of the
+ elements can not be converted to integer.
+ '''
+
+ harray = [int(x, 16) for x in sarray]
+ for name, desc in dtd_descriptor.iteritems():
+ attr_value = 0
+ total_width = 0
+ for tup in desc:
+ if isinstance(tup, tuple):
+ offset, shift, width = tup
+ else:
+ offset, shift, width = tup, 0, 8
+
+ mask = (1 << width) - 1
+ attr_value = (attr_value << width) + (
+ (harray[offset] >> shift) & mask)
+ total_width += width
+ setattr(self, PREFIX + name, attr_value)
+ setattr(self, 'max_' + PREFIX + name, (1 << total_width) - 1)
+
+ def __str__(self):
+ text = []
+ for name in sorted(dtd_descriptor.keys()):
+ text.append('%20s: %d' % (name, getattr(self, PREFIX + name)))
+ return '\n'.join(text)
+
+ def inhex(self):
+ '''Generate contents of the DTD as a 18 byte ASCII hex array.'''
+
+ result = [0] * 18
+ for name, desc in dtd_descriptor.iteritems():
+ attr_value = getattr(self, PREFIX + name)
+ rdesc = list(desc)
+ rdesc.reverse()
+ for tup in rdesc:
+ if isinstance(tup, tuple):
+ offset, shift, width = tup
+ else:
+ offset, shift, width = tup, 0, 8
+
+ mask = (1 << width) - 1
+ value = attr_value & mask
+ attr_value = attr_value >> width
+ result[offset] = (result[offset] & ~(
+ mask << shift)) | (value << shift)
+
+ return ' '.join('%2.2x' % x for x in result)
+
+ def handle_input(self, name):
+ '''Get user input and set a new parameter value if required.
+
+ Display the parameter name, its current value, and prompt user for a
+ new value.
+
+ If the user enters a dot, stop processing (return True).
+
+ Empty user input means that this parameter does not have to change,
+ but the next parameter should be prompted.
+
+ If input is non-empty, it is interpreted as a hex number, checked if
+ it fits the parameter and the new parameter value is set if checks
+ pass.
+
+ Inputs:
+
+ name - a string, parameter name, a key in dtd_descriptor
+
+ Returns:
+
+ Boolean, True meaning no more field are required to be modified, False
+ meaning that more field mods need to be prompted..
+ '''
+
+ param = PREFIX + name
+ vmax = getattr(self, 'max_' + param)
+ new_value = raw_input('%s : %d ' % (name, getattr(self, param)))
+ if new_value == '':
+ return False
+ if new_value == '.':
+ return True
+ new_int = int(new_value)
+ if new_int > vmax:
+ print '%s exceeds maximum for %s (%d)' % (new_value, name, vmax)
+ else:
+ setattr(self, param, new_int)
+ return False
+
+def main(args):
+ if args[0] == '-m':
+ modify = True
+ base = 1
+ else:
+ modify = False
+ base = 0
+
+ d = DTD()
+ d.init(args[base:])
+ if modify:
+ for line in str(d).splitlines():
+ if d.handle_input(line.split(':')[0].strip()):
+ break
+ print d
+ if modify:
+ print d.inhex()
+
+
+if __name__ == '__main__':
+ try:
+ main(sys.argv[1:])
+ except (ValueError, IndexError):
+ print """
+A string of 18 byte values in hex is required.
+'-m' preceding the string will allow setting new parameter values.
+"""
+ sys.exit(1)