Merge branch 'release/4.5.0'

CHANGELOG.rst

@@ -4,6 +4,11 @@
 Changelog
 #########
 
+v4.5.0
+    Released: 2015-10-15 16:50:57 +0200
+
+    - Add ``chvt`` workaround as suggested by Cody Christensen.
+
 v4.4.2
     Released: 2015-07-31 15:14:59 +0200
 

doc/man/thinkpad-rotate.1.rst

@@ -110,15 +110,38 @@ You can set the following option:
 
 ``rotate.xrandr_bug_workaround``
     On Ubuntu 15.04, XRandr has `a bug`__ which turns the screen black when
-    rotating with no external screen attached. If you set this to ``true``, the
-    rotate hook will only act when an external screen is attached. In the cases
-    you want to rotate the screen without external screens do the following:
-    Call ``thinkpad-rotate``, the screen will turn black. Then go to another
-    terminal with [Ctrl][Alt][F1] and back to the graphical one with
-    [Ctrl][Alt][F7]. *Default: false*.
+    rotating with no external screen attached.
 
     __ https://bugs.launchpad.net/ubuntu/+source/x11-xserver-utils/+bug/1451798
 
+    This is problematic when the rotation is executed from a hardware event
+    hook. Then the screen is physically laying on the keyboard and one cannot
+    do anything. A workaround is to go to another terminal with [Ctrl][Alt][F1]
+    and back to the graphical one with [Ctrl][Alt][F7].
+
+    As contributed by Cody Christensen, that can be automated with ``chvt``.
+    This way the hook will work in a useful way for users with that XRandr bug.
+    However, this program needs superuser privileges. One can use ``sudo`` to
+    allow oneself to call this program without a password entry. Add the
+    following line in a file like ``/etc/sudoers.d/chvt``::
+
+        myuser  ALL = NOPASSWD: /bin/chvt
+
+    Replace ``myuser`` with your username! Then check with ``visudo -c``
+    whether the syntax is fine.
+
+    |project| can figure out whether this line is implemented by querying
+    ``sudo -l`` for a list of available commands with higher privileges. If you
+    set this option to ``true`` and the line is configured, it will call ``chvt
+    6; chvt 7`` after the rotation and before the hook.
+
+    If ``chvt`` cannot be used, the hook will be disabled by enabling this
+    option. That way you can manually rotate the contents of the display with
+    ``thinkpad-rotate``, press [Ctrl][Alt][F1] and [Ctrl][Alt][F7] and only
+    then physically rotate the screen. The hook will not fire and rotate back.
+
+    *Default: false*.
+
 ``screen.internal``
     The ``xrandr`` name for the internal monitor. *Default: LVDS1*
 

tps/rotate.py

@@ -28,7 +28,7 @@ def main():
     config = tps.config.get_config()
 
     if options.via_hook:
-        xrandr_bug_workaround(config)
+        xrandr_bug_fail_early(config)
 
     try:
         new_direction = new_rotation(
@@ -86,6 +86,9 @@ def rotate_to(direction, config):
         logger.info('TouchPad was not found, could not be (de)activated.')
         logger.debug('Exception was: “%s”', str(e))
 
+    if needs_xrandr_bug_workaround(config) and can_use_chvt():
+        toggle_virtual_terminal()
+
     tps.hooks.postrotate(direction, config)
 
 
@@ -112,20 +115,83 @@ def new_rotation(current, desired_str, config):
     return new
 
 
-def xrandr_bug_workaround(config):
+def can_use_chvt():
+    '''
+    Checks whether ``chvt`` can be called with ``sudo`` without a password.
+
+    The ``sudo`` command has the ``-n`` option which will just make the command
+    fail when the user does not have the appropriate permissions. The problem
+    with ``chvt`` is that it does not have any intelligent command line
+    argument parsing. If will return code 1 if no argument is given, the same
+    code that ``sudo`` gives when no permission is available. Therefore I chose
+    to use ``sudo -l` to get the whole list and see whether the full path to
+    ``chvt`` is in there. This might break on Fedora where the ``usr``-merge
+    has been done now.
+
+    The following line is needed in a file like ``/etc/sudoers.d/chvt``::
+
+        myuser  ALL = NOPASSWD: /bin/chvt
+
+    You have to replace ``myuser`` which your username. Giving too broad
+    permissions to every other user account is probably not a good idea.
+
+    :rtype: bool
+    '''
+    command = ['sudo', '-l']
+    output = tps.check_output(command, logger)
+
+    return b'/bin/chvt' in output
+
+
+def toggle_virtual_terminal():
+    '''
+    '''
+    assert can_use_chvt()
+    tps.check_call(['sudo', '-n', 'chvt', '6'], logger)
+    tps.check_call(['sudo', '-n', 'chvt', '7'], logger)
+
+
+def has_external_screens(config):
+    '''
+    Checks whether any external screens are attached.
     '''
-    XRandr has a `bug in Ubuntu`__, maybe even in other distributions. This
-    functions will abort if there is no external screen attached.
+    externals = tps.screen.get_externals(config['screen']['internal'])
+    return len(externals) > 0
+
+
+def needs_xrandr_bug_workaround(config):
+    '''
+    Determines whether xrandr bug needs to be worked around.
+
+    XRandr has a `bug in Ubuntu`__, maybe even in other distributions. In
+    Ubuntu 15.04 a workaround is to change the virtual terminal to a different
+    one and back to the seventh, the graphical one. This can be automated using
+    the ``chvt`` command which requires superuser privileges. An entry in the
+    sudo file can let the normal user execute this program.
 
     __ https://bugs.launchpad.net/ubuntu/+source/x11-xserver-utils/+bug/1451798
     '''
+    # Do nothing if workaround is not requested.
     if not config['rotate'].getboolean('xrandr_bug_workaround'):
-        return
+        return False
 
-    externals = tps.screen.get_externals(config['screen']['internal'])
-    if (len(externals) == 0):
+    logger.debug('xrandr bug workaround requested')
+
+    # Do nothing if an external screen is attached. The bug does not appear
+    # then.
+    if has_external_screens(config):
+        return False
+
+    return True
+
+
+def xrandr_bug_fail_early(config):
+    '''
+    Quits the program if xrandr bug cannot be coped with.
+    '''
+    if needs_xrandr_bug_workaround(config) and not can_use_chvt():
         logger.warning('Aborting since there are no external screens attached '
-                       'and XRandr bug workout is enabled.')
+                       'and XRandr bug workaround is enabled.')
         sys.exit(1)