On Sun, Aug 04, 2019 at 10:16:35PM +0200, Sam Ravnborg wrote: > Many panel drivers duplicate logic to prevent prepare to be called > for a panel that is already prepared. > Likewise for enable. > > Implement this logic in drm_panel so the individual drivers > no longer needs this. > A panel is considered prepared/enabled only if the prepare/enable call > succeeds. > For disable/unprepare it is unconditionally considered > disabled/unprepared. Hi Sam, I did a similar thing a few years ago [1]. IIRC it was well received and just needed some nits cleaned up. Unfortunately I lost interest^W^W switched to other things and dropped it. So thanks for picking this back up! Fast forward to today, I still think it's a good idea but I want to make sure this won't negatively interact with the self refresh helpers. With the helpers in place, it's possible to call disable consecutively (ie: once to enter self refresh and again to actually shut down). I did a quick pass and it looks like this patch might break that behavior, so you might want to take that into account. Sean [1]- https://patchwork.freedesktop.org/series/30712/ > > This allows calls to prepare/enable again, even if there were > some issue disabling a regulator or similar during disable/unprepare. > > Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx> > Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> > Cc: Maxime Ripard <maxime.ripard@xxxxxxxxxxx> > Cc: Sean Paul <sean@xxxxxxxxxx> > Cc: Thierry Reding <thierry.reding@xxxxxxxxx> > Cc: Sam Ravnborg <sam@xxxxxxxxxxxx> > Cc: David Airlie <airlied@xxxxxxxx> > Cc: Daniel Vetter <daniel@xxxxxxxx> > --- > drivers/gpu/drm/drm_panel.c | 66 ++++++++++++++++++++++++++++++------- > include/drm/drm_panel.h | 21 ++++++++++++ > 2 files changed, 75 insertions(+), 12 deletions(-) > > diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c > index da19d5b4a2f4..0853764040de 100644 > --- a/drivers/gpu/drm/drm_panel.c > +++ b/drivers/gpu/drm/drm_panel.c > @@ -66,10 +66,21 @@ EXPORT_SYMBOL(drm_panel_init); > */ > int drm_panel_prepare(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->prepare) > - return panel->funcs->prepare(panel); > + int ret = -ENOSYS; > > - return panel ? -ENOSYS : -EINVAL; > + if (!panel) > + return -EINVAL; > + > + if (panel->prepared) > + return 0; > + > + if (panel->funcs && panel->funcs->prepare) > + ret = panel->funcs->prepare(panel); > + > + if (ret >= 0) > + panel->prepared = true; > + > + return ret; > } > EXPORT_SYMBOL(drm_panel_prepare); > > @@ -85,10 +96,21 @@ EXPORT_SYMBOL(drm_panel_prepare); > */ > int drm_panel_enable(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->enable) > - return panel->funcs->enable(panel); > + int ret = -ENOSYS; > > - return panel ? -ENOSYS : -EINVAL; > + if (!panel) > + return -EINVAL; > + > + if (panel->enabled) > + return 0; > + > + if (panel->funcs && panel->funcs->enable) > + ret = panel->funcs->enable(panel); > + > + if (ret >= 0) > + panel->enabled = true; > + > + return ret; > } > EXPORT_SYMBOL(drm_panel_enable); > > @@ -104,10 +126,20 @@ EXPORT_SYMBOL(drm_panel_enable); > */ > int drm_panel_disable(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->disable) > - return panel->funcs->disable(panel); > + int ret = -ENOSYS; > > - return panel ? -ENOSYS : -EINVAL; > + if (!panel) > + return -EINVAL; > + > + if (!panel->enabled) > + return 0; > + > + if (panel->funcs && panel->funcs->disable) > + ret = panel->funcs->disable(panel); > + > + panel->enabled = false; > + > + return ret; > } > EXPORT_SYMBOL(drm_panel_disable); > > @@ -124,10 +156,20 @@ EXPORT_SYMBOL(drm_panel_disable); > */ > int drm_panel_unprepare(struct drm_panel *panel) > { > - if (panel && panel->funcs && panel->funcs->unprepare) > - return panel->funcs->unprepare(panel); > + int ret = -ENOSYS; > > - return panel ? -ENOSYS : -EINVAL; > + if (!panel) > + return -EINVAL; > + > + if (!panel->prepared) > + return 0; > + > + if (panel->funcs && panel->funcs->unprepare) > + ret = panel->funcs->unprepare(panel); > + > + panel->prepared = false; > + > + return ret; > } > EXPORT_SYMBOL(drm_panel_unprepare); > > diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h > index 624bd15ecfab..7493500fc9bd 100644 > --- a/include/drm/drm_panel.h > +++ b/include/drm/drm_panel.h > @@ -65,6 +65,9 @@ struct drm_panel_funcs { > * @prepare: > * > * Turn on panel and perform set up. > + * When the panel is successfully prepared the prepare() function > + * will not be called again until the panel has been unprepared. > + * > */ > int (*prepare)(struct drm_panel *panel); > > @@ -72,6 +75,8 @@ struct drm_panel_funcs { > * @enable: > * > * Enable panel (turn on back light, etc.). > + * When the panel is successfully enabled the enable() function > + * will not be called again until the panel has been disabled. > */ > int (*enable)(struct drm_panel *panel); > > @@ -79,6 +84,7 @@ struct drm_panel_funcs { > * @disable: > * > * Disable panel (turn off back light, etc.). > + * If the panel is already disabled the disable() function is not called. > */ > int (*disable)(struct drm_panel *panel); > > @@ -86,6 +92,7 @@ struct drm_panel_funcs { > * @unprepare: > * > * Turn off panel. > + * If the panel is already unprepared the unprepare() function is not called. > */ > int (*unprepare)(struct drm_panel *panel); > > @@ -145,6 +152,20 @@ struct drm_panel { > * Panel entry in registry. > */ > struct list_head list; > + > + /** > + * @prepared: > + * > + * Set to true when the panel is successfully prepared. > + */ > + bool prepared; > + > + /** > + * @enabled: > + * > + * Set to true when the panel is successfully enabled. > + */ > + bool enabled; > }; > > void drm_panel_init(struct drm_panel *panel); > -- > 2.20.1 > -- Sean Paul, Software Engineer, Google / Chromium OS
