lkml.org 
[lkml]   [2024]   [May]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFT PATCH v2 07/48] drm/panel: edp: Add a comment about unprepare+disable at shutdown/remove
Date
It's the responsibility of a correctly written DRM modeset driver to
call drm_atomic_helper_shutdown() at shutdown time and that should be
disabling / unpreparing the panel if needed. Panel drivers shouldn't
be calling these functions themselves.

A recent effort was made to fix as many DRM modeset drivers as
possible [1] [2] [3] and most drivers are fixed now.

Unfortunately, it's very difficult to know exactly which DRM modeset
drivers are using panel-edp due to the sheer number of panels it
handles. For now, we'll leave the calls and just add a comment to keep
people from copying this code.

[1] https://lore.kernel.org/r/20230901234015.566018-1-dianders@chromium.org
[2] https://lore.kernel.org/r/20230901234202.566951-1-dianders@chromium.org
[3] https://lore.kernel.org/r/20230921192749.1542462-1-dianders@chromium.org

Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

Changes in v2:
- Only handle 1 panel per patch.
- Split removal of prepared/enabled from handling of remove/shutdown.
- panel-edp and panel-simple just get a comment now.

drivers/gpu/drm/panel/panel-edp.c | 33 +++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c
index 344f67871d41..9c4c5c0e39a3 100644
--- a/drivers/gpu/drm/panel/panel-edp.c
+++ b/drivers/gpu/drm/panel/panel-edp.c
@@ -944,13 +944,34 @@ static int panel_edp_probe(struct device *dev, const struct panel_desc *desc,
return err;
}

-static void panel_edp_remove(struct device *dev)
+static void panel_edp_shutdown(struct device *dev)
{
struct panel_edp *panel = dev_get_drvdata(dev);

- drm_panel_remove(&panel->base);
+ /*
+ * NOTE: the following two calls don't really belong here. It is the
+ * responsibility of a correctly written DRM modeset driver to call
+ * drm_atomic_helper_shutdown() at shutdown time and that should
+ * cause the panel to be disabled / unprepared if needed. For now,
+ * however, we'll keep these calls due to the sheer number of
+ * different DRM modeset drivers used with panel-edp. The fact that
+ * we're calling these and _also_ the drm_atomic_helper_shutdown()
+ * will try to disable/unprepare means that we can get a warning about
+ * trying to disable/unprepare an already disabled/unprepared panel,
+ * but that's something we'll have to live with until we've confirmed
+ * that all DRM modeset drivers are properly calling
+ * drm_atomic_helper_shutdown().
+ */
drm_panel_disable(&panel->base);
drm_panel_unprepare(&panel->base);
+}
+
+static void panel_edp_remove(struct device *dev)
+{
+ struct panel_edp *panel = dev_get_drvdata(dev);
+
+ drm_panel_remove(&panel->base);
+ panel_edp_shutdown(dev);

pm_runtime_dont_use_autosuspend(dev);
pm_runtime_disable(dev);
@@ -961,14 +982,6 @@ static void panel_edp_remove(struct device *dev)
panel->drm_edid = NULL;
}

-static void panel_edp_shutdown(struct device *dev)
-{
- struct panel_edp *panel = dev_get_drvdata(dev);
-
- drm_panel_disable(&panel->base);
- drm_panel_unprepare(&panel->base);
-}
-
static const struct display_timing auo_b101ean01_timing = {
.pixelclock = { 65300000, 72500000, 75000000 },
.hactive = { 1280, 1280, 1280 },
--
2.45.0.rc1.225.g2a3ae87e7f-goog

\
 
 \ /
  Last update: 2024-05-27 18:15    [W:0.606 / U:0.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site