diff options
Diffstat (limited to 'Documentation/gpu/todo.rst')
| -rw-r--r-- | Documentation/gpu/todo.rst | 35 |
1 files changed, 16 insertions, 19 deletions
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst index 2ea6ffc9b22b..96c453980ab6 100644 --- a/Documentation/gpu/todo.rst +++ b/Documentation/gpu/todo.rst @@ -475,25 +475,22 @@ Remove disable/unprepare in remove/shutdown in panel-simple and panel-edp As of commit d2aacaf07395 ("drm/panel: Check for already prepared/enabled in drm_panel"), we have a check in the drm_panel core to make sure nobody double-calls prepare/enable/disable/unprepare. Eventually that should probably -be turned into a WARN_ON() or somehow made louder, but right now we actually -expect it to trigger and so we don't want it to be too loud. - -Specifically, that warning will trigger for panel-edp and panel-simple at -shutdown time because those panels hardcode a call to drm_panel_disable() -and drm_panel_unprepare() at shutdown and remove time that they call regardless -of panel state. On systems with a properly coded DRM modeset driver that -calls drm_atomic_helper_shutdown() this is pretty much guaranteed to cause -the warning to fire. - -Unfortunately we can't safely remove the calls in panel-edp and panel-simple -until we're sure that all DRM modeset drivers that are used with those panels -properly call drm_atomic_helper_shutdown(). This TODO item is to validate -that all DRM modeset drivers used with panel-edp and panel-simple properly -call drm_atomic_helper_shutdown() and then remove the calls to -disable/unprepare from those panels. Alternatively, this TODO item could be -removed by convincing stakeholders that those calls are fine and downgrading -the error message in drm_panel_disable() / drm_panel_unprepare() to a -debug-level message. +be turned into a WARN_ON() or somehow made louder. + +At the moment, we expect that we may still encounter the warnings in the +drm_panel core when using panel-simple and panel-edp. Since those panel +drivers are used with a lot of different DRM modeset drivers they still +make an extra effort to disable/unprepare the panel themsevles at shutdown +time. Specifically we could still encounter those warnings if the panel +driver gets shutdown() _before_ the DRM modeset driver and the DRM modeset +driver properly calls drm_atomic_helper_shutdown() in its own shutdown() +callback. Warnings could be avoided in such a case by using something like +device links to ensure that the panel gets shutdown() after the DRM modeset +driver. + +Once all DRM modeset drivers are known to shutdown properly, the extra +calls to disable/unprepare in remove/shutdown in panel-simple and panel-edp +should be removed and this TODO item marked complete. Contact: Douglas Anderson <dianders@chromium.org> |