diff options
| author | Douglas Anderson <dianders@chromium.org> | 2024-06-21 13:44:29 -0700 |
|---|---|---|
| committer | Douglas Anderson <dianders@chromium.org> | 2024-07-22 09:00:58 -0700 |
| commit | f00bfaca704ca1a2c4e31501a0a7d4ee434e73a7 (patch) | |
| tree | 7023adb2c1d19e4a43da2f8efce834eee5386688 /drivers/gpu/drm/drm_panel.c | |
| parent | 1f7ce4316d8c8ca8fdf5e477fee91012420b1fa3 (diff) | |
drm/panel: Avoid warnings w/ panel-simple/panel-edp at shutdown
At shutdown if you've got a _properly_ coded DRM modeset driver then
you'll get these two warnings at shutdown time:
Skipping disable of already disabled panel
Skipping unprepare of already unprepared panel
These warnings are ugly and sound concerning, but they're actually a
sign of a properly working system. That's not great.
We're not ready to get rid of the calls to drm_panel_disable() and
drm_panel_unprepare() because we're not 100% convinced that all DRM
modeset drivers are properly calling drm_atomic_helper_shutdown() or
drm_helper_force_disable_all() at the right times. However, having the
warning show up for correctly working systems is bad.
As a bit of a workaround, add some "if" tests to try to avoid the
warning on correctly working systems. Also add some comments and
update the TODO items in the hopes that future developers won't be too
confused by what's going on here.
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240621134427.1.Ieb287c2c3ee3f6d3b0d5f49b29f746b93621749c@changeid
Diffstat (limited to 'drivers/gpu/drm/drm_panel.c')
| -rw-r--r-- | drivers/gpu/drm/drm_panel.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index cfbe020de54e..19ab0a794add 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -161,6 +161,15 @@ int drm_panel_unprepare(struct drm_panel *panel) if (!panel) return -EINVAL; + /* + * If you are seeing the warning below it likely means one of two things: + * - Your panel driver incorrectly calls drm_panel_unprepare() in its + * shutdown routine. You should delete this. + * - You are using panel-edp or panel-simple and your DRM modeset + * driver's shutdown() callback happened after the panel's shutdown(). + * In this case the warning is harmless though ideally you should + * figure out how to reverse the order of the shutdown() callbacks. + */ if (!panel->prepared) { dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n"); return 0; @@ -245,6 +254,15 @@ int drm_panel_disable(struct drm_panel *panel) if (!panel) return -EINVAL; + /* + * If you are seeing the warning below it likely means one of two things: + * - Your panel driver incorrectly calls drm_panel_disable() in its + * shutdown routine. You should delete this. + * - You are using panel-edp or panel-simple and your DRM modeset + * driver's shutdown() callback happened after the panel's shutdown(). + * In this case the warning is harmless though ideally you should + * figure out how to reverse the order of the shutdown() callbacks. + */ if (!panel->enabled) { dev_warn(panel->dev, "Skipping disable of already disabled panel\n"); return 0; |