summaryrefslogtreecommitdiffstats
path: root/include
diff options
context:
space:
mode:
authorDouglas Anderson <dianders@chromium.org>2023-07-27 10:16:29 -0700
committerDouglas Anderson <dianders@chromium.org>2023-08-01 07:35:36 -0700
commitd2aacaf07395bd798373cbec6af05fff4147aff3 (patch)
treea70aa3b04c5c53ab75e3d6d118059e0f7fa35b98 /include
parent2ca376ef18f6bc36a1bc9d53a19026e5fc16ab76 (diff)
downloadlinux-stable-d2aacaf07395bd798373cbec6af05fff4147aff3.tar.gz
linux-stable-d2aacaf07395bd798373cbec6af05fff4147aff3.tar.bz2
linux-stable-d2aacaf07395bd798373cbec6af05fff4147aff3.zip
drm/panel: Check for already prepared/enabled in drm_panel
In a whole pile of panel drivers, we have code to make the prepare/unprepare/enable/disable callbacks behave as no-ops if they've already been called. It's silly to have this code duplicated everywhere. Add it to the core instead so that we can eventually delete it from all the drivers. Note: to get some idea of the duplicated code, try: git grep 'if.*>prepared' -- drivers/gpu/drm/panel git grep 'if.*>enabled' -- drivers/gpu/drm/panel NOTE: arguably, the right thing to do here is actually to skip this patch and simply remove all the extra checks from the individual drivers. Perhaps the checks were needed at some point in time in the past but maybe they no longer are? Certainly as we continue transitioning over to "panel_bridge" then we expect there to be much less variety in how these calls are made. When we're called as part of the bridge chain, things should be pretty simple. In fact, there was some discussion in the past about these checks [1], including a discussion about whether the checks were needed and whether the calls ought to be refcounted. At the time, I decided not to mess with it because it felt too risky. Looking closer at it now, I'm fairly certain that nothing in the existing codebase is expecting these calls to be refcounted. The only real question is whether someone is already doing something to ensure prepare()/unprepare() match and enabled()/disable() match. I would say that, even if there is something else ensuring that things match, there's enough complexity that adding an extra bool and an extra double-check here is a good idea. Let's add a drm_warn() to let people know that it's considered a minor error to take advantage of drm_panel's double-checking but we'll still make things work fine. We'll also add an entry to the official DRM todo list to remove the now pointless check from the panels after this patch lands and, eventually, fixup anyone who is triggering the new warning. [1] https://lore.kernel.org/r/20210416153909.v4.27.I502f2a92ddd36c3d28d014dd75e170c2d405a0a5@changeid Acked-by: Neil Armstrong <neil.armstrong@linaro.org> Reviewed-by: Maxime Ripard <mripard@kernel.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.2.I59b417d4c29151cc2eff053369ec4822b606f375@changeid
Diffstat (limited to 'include')
-rw-r--r--include/drm/drm_panel.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 432fab2347eb..c6cf75909389 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -198,6 +198,20 @@ struct drm_panel {
* the panel is powered up.
*/
bool prepare_prev_first;
+
+ /**
+ * @prepared:
+ *
+ * If true then the panel has been prepared.
+ */
+ bool prepared;
+
+ /**
+ * @enabled:
+ *
+ * If true then the panel has been enabled.
+ */
+ bool enabled;
};
void drm_panel_init(struct drm_panel *panel, struct device *dev,