Allow more values for the qt.force_software_rendering setting

doc/changelog.asciidoc

@@ -37,6 +37,9 @@ Changed
   (like `:config-cycle`).
 - QtWebEngine: On Qt 5.11.1, no reloads are needed anymore when switching
   between pages with changed settings (e.g. `content.javascript.enabled`).
+- The `qt.force_software_rendering` setting changed from a boolean to taking
+  different values (`software-opengl`, `qt-quick` and `chromium`) for different
+  kinds of software rendering workarounds.
 
 v1.3.2 (unreleased)
 -------------------

doc/help/settings.asciidoc

@@ -2579,12 +2579,19 @@ Default: empty
 [[qt.force_software_rendering]]
 === qt.force_software_rendering
 Force software rendering for QtWebEngine.
-This is needed for QtWebEngine to work with Nouveau drivers.
+This is needed for QtWebEngine to work with Nouveau drivers and can be useful in other scenarios related to graphic issues.
 This setting requires a restart.
 
-Type: <<types,Bool>>
+Type: <<types,String>>
 
-Default: +pass:[false]+
+Valid values:
+
+ * +software-opengl+: Tell LibGL to use a software implementation of GL (`LIBGL_ALWAYS_SOFTWARE` / `QT_XCB_FORCE_SOFTWARE_OPENGL`)
+ * +qt-quick+: Tell Qt Quick to use a software renderer instead of OpenGL. (`QT_QUICK_BACKEND=software`)
+ * +chromium+: Tell Chromium to disable GPU support and use Skia software rendering instead. (`--disable-gpu`)
+ * +none+: Don't force software rendering.
+
+Default: +pass:[none]+
 
 This setting is only available with the QtWebEngine backend.
 

qutebrowser/config/configdata.yml

@@ -150,14 +150,24 @@ force_software_rendering:
   renamed: qt.force_software_rendering
 
 qt.force_software_rendering:
-  type: Bool
+  type:
-  default: false
+    name: String
+    valid_values:
+      - software-opengl: Tell LibGL to use a software implementation of GL
+            (`LIBGL_ALWAYS_SOFTWARE` / `QT_XCB_FORCE_SOFTWARE_OPENGL`)
+      - qt-quick: Tell Qt Quick to use a software renderer instead of OpenGL.
+            (`QT_QUICK_BACKEND=software`)
+      - chromium: Tell Chromium to disable GPU support and use Skia software
+            rendering instead. (`--disable-gpu`)
+      - none: Don't force software rendering.
+  default: none
   backend: QtWebEngine
   restart: true
   desc: >-
     Force software rendering for QtWebEngine.
 
-    This is needed for QtWebEngine to work with Nouveau drivers.
+    This is needed for QtWebEngine to work with Nouveau drivers and can be
+    useful in other scenarios related to graphic issues.
 
 qt.force_platform:
   type:

qutebrowser/config/configfiles.py

@@ -277,6 +277,15 @@ class YamlConfig(QObject):
                     settings[name][scope] = 'always' if val else 'never'
                     self._mark_changed()
 
+        # qt.force_software_rendering isn't a boolean anymore
+        name = 'qt.force_software_rendering'
+        if name in settings:
+            for scope, val in settings[name].items():
+                if isinstance(val, bool):
+                    settings[name][scope] = ('software-opengl' if val
+                                             else 'none')
+                    self._mark_changed()
+
         return settings
 
     def _validate(self, settings):

qutebrowser/config/configinit.py

@@ -83,9 +83,12 @@ def early_init(args):
 
 def _init_envvars():
     """Initialize environment variables which need to be set early."""
-    if (objects.backend == usertypes.Backend.QtWebEngine and
+    if objects.backend == usertypes.Backend.QtWebEngine:
-            config.val.qt.force_software_rendering):
+        software_rendering = config.val.qt.force_software_rendering
-        os.environ['QT_XCB_FORCE_SOFTWARE_OPENGL'] = '1'
+        if software_rendering == 'software-opengl':
+            os.environ['QT_XCB_FORCE_SOFTWARE_OPENGL'] = '1'
+        elif software_rendering == 'qt-quick':
+            os.environ['QT_QUICK_BACKEND'] = 'software'
 
     if config.val.qt.force_platform is not None:
         os.environ['QT_QPA_PLATFORM'] = config.val.qt.force_platform
@@ -163,11 +166,13 @@ def qt_args(namespace):
 
     argv += ['--' + arg for arg in config.val.qt.args]
 
-    if (objects.backend == usertypes.Backend.QtWebEngine and
+    if objects.backend == usertypes.Backend.QtWebEngine:
-            not qtutils.version_check('5.11', compiled=False)):
+        if not qtutils.version_check('5.11', compiled=False):
-        # WORKAROUND equivalent to
+            # WORKAROUND equivalent to
-        # https://codereview.qt-project.org/#/c/217932/
+            # https://codereview.qt-project.org/#/c/217932/
-        # Needed for Qt < 5.9.5 and < 5.10.1
+            # Needed for Qt < 5.9.5 and < 5.10.1
-        argv.append('--disable-shared-workers')
+            argv.append('--disable-shared-workers')
+        if config.val.qt.force_software_rendering == 'chromium':
+            argv.append('--disable-gpu')
 
     return argv

qutebrowser/misc/backendproblem.py

@@ -185,7 +185,7 @@ def _handle_nouveau_graphics():
         return
 
     button = _Button("Force software rendering", 'qt.force_software_rendering',
-                     True)
+                     'chromium')
     _show_dialog(
         backend=usertypes.Backend.QtWebEngine,
         because="you're using Nouveau graphics",
@@ -194,9 +194,9 @@ def _handle_nouveau_graphics():
              "<p>This allows you to use the newer QtWebEngine backend (based "
              "on Chromium) but could have noticeable performance impact "
              "(depending on your hardware). "
-             "This sets the <i>qt.force_software_rendering = True</i> option "
+             "This sets the <i>qt.force_software_rendering = 'chromium'</i> "
-             "(if you have a <i>config.py</i> file, you'll need to set this "
+             "option (if you have a <i>config.py</i> file, you'll need to set "
-             "manually).</p>",
+             "this manually).</p>",
         buttons=[button],
     )
 

tests/end2end/test_invocations.py

@@ -375,19 +375,3 @@ def test_qute_settings_persistence(short_tmpdir, request, quteproc_new):
 
     quteproc_new.start(args)
     assert quteproc_new.get_setting('search.ignore_case') == 'always'
-
-
-@pytest.mark.no_xvfb
-@pytest.mark.no_ci
-@pytest.mark.not_mac
-def test_force_software_rendering(request, quteproc_new):
-    """Make sure we can force software rendering with -s."""
-    if not request.config.webengine:
-        pytest.skip("Only runs with QtWebEngine")
-
-    args = (_base_args(request.config) +
-            ['--temp-basedir', '-s', 'qt.force_software_rendering', 'true'])
-    quteproc_new.start(args)
-    quteproc_new.open_path('chrome://gpu')
-    message = 'Canvas: Software only, hardware acceleration unavailable'
-    assert message in quteproc_new.get_content()

tests/unit/config/test_configfiles.py

@@ -252,6 +252,19 @@ class TestYaml:
         data = autoconfig.read()
         assert data['tabs.favicons.show']['global'] == expected
 
+    @pytest.mark.parametrize('force, expected', [
+        (True, 'software-opengl'),
+        (False, 'none'),
+    ])
+    def test_force_software_rendering(self, yaml, autoconfig, force, expected):
+        autoconfig.write({'qt.force_software_rendering': {'global': force}})
+
+        yaml.load()
+        yaml._save()
+
+        data = autoconfig.read()
+        assert data['qt.force_software_rendering']['global'] == expected
+
     def test_renamed_key_unknown_target(self, monkeypatch, yaml,
                                         autoconfig):
         """A key marked as renamed with invalid name should raise an error."""

tests/unit/config/test_configinit.py

@@ -288,8 +288,10 @@ class TestEarlyInit:
         config.instance.set_str('fonts.monospace', 'Terminus')
 
     @pytest.mark.parametrize('config_opt, config_val, envvar, expected', [
-        ('qt.force_software_rendering', True,
+        ('qt.force_software_rendering', 'software-opengl',
          'QT_XCB_FORCE_SOFTWARE_OPENGL', '1'),
+        ('qt.force_software_rendering', 'qt-quick',
+         'QT_QUICK_BACKEND', 'software'),
         ('qt.force_platform', 'toaster', 'QT_QPA_PLATFORM', 'toaster'),
         ('qt.highdpi', True, 'QT_AUTO_SCREEN_SCALE_FACTOR', '1'),
         ('window.hide_decoration', True,
@@ -397,6 +399,14 @@ class TestQtArgs:
         expected = [sys.argv[0], '--disable-shared-workers']
         assert configinit.qt_args(parsed) == expected
 
+    def test_disable_gpu(self, config_stub, monkeypatch, parser):
+        config_stub.val.qt.force_software_rendering = 'chromium'
+        monkeypatch.setattr(configinit.objects, 'backend',
+                            usertypes.Backend.QtWebEngine)
+        parsed = parser.parse_args([])
+        expected = [sys.argv[0], '--disable-gpu']
+        assert configinit.qt_args(parsed) == expected
+
 
 @pytest.mark.parametrize('arg, confval, used', [
     # overridden by commandline arg