Hi Sean, On Mon, Aug 05, 2019 at 01:01:20PM -0400, Sean Paul wrote: > 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. Is this semantics documented somewhere ? The documentation of the panel disable operation is pretty terse, and we need to explicitly state who of the caller and callee needs to track the state. > [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); -- Regards, Laurent Pinchart
