docs-rst: fix LaTeX \DURole renewcommand with Sphinx 1.3+

commit e2a91f4f42018994d7424d405900d17eba6555d0 upstream.

PDF build on Kernel 4.9-rc? returns an error with Sphinx 1.3.x
and Sphinx 1.4.x, when trying to solve some cross-references.

The solution is to redefine the \DURole macro.

However, this is redefined too late. Move such redefinition to
LaTeX preamble and bind it to just the Sphinx versions where the
error is known to be present.

Tested by building the documentation on interactive mode:
	make PDFLATEX=xelatex -C Documentation/output/./latex

Fixes: e61a39baf74d ("[media] index.rst: Fix LaTeX error in interactive mode on Sphinx 1.4.x")
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 5 insertions, 6 deletions

diff --git a/Documentation/conf.py b/Documentation/conf.py
index bf6f310e5170..d769cd89a9f7 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -37,7 +37,7 @@ from load_config import loadConfig
 extensions = ['kernel-doc', 'rstFlatTable', 'kernel_include', 'cdomain']
 
 # The name of the math extension changed on Sphinx 1.4
-if minor > 3:
+if major == 1 and minor > 3:
     extensions.append("sphinx.ext.imgmath")
 else:
     extensions.append("sphinx.ext.pngmath")
@@ -332,6 +332,10 @@ latex_elements = {
      '''
 }
 
+# Fix reference escape troubles with Sphinx 1.4.x
+if major == 1 and minor > 3:
+    latex_elements['preamble']  += '\\renewcommand*{\\DUrole}[2]{ #2 }\n'
+
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
diff --git a/Documentation/media/index.rst b/Documentation/media/index.rst
index e347a3e7bdef..7f8f0af620ce 100644
--- a/Documentation/media/index.rst
+++ b/Documentation/media/index.rst
@@ -1,11 +1,6 @@
 Linux Media Subsystem Documentation
 ===================================
 
-.. Sphinx 1.4.x has a definition for DUrole that doesn't work on alltt blocks
-.. raw:: latex
-
-        \renewcommand*{\DUrole}[2]{ #2 }
-
 Contents:
 
 .. toctree::