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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Sam, Thank you for the patch. 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. > > This allows calls to prepare/enable again, even if there were > some issue disabling a regulator or similar during disable/unprepare. Is this the right place to handle this ? Shouldn't the upper layers ensure than enable/disable and prepare/unprepare are correcty balanced, and not called multiple times ? Adding enabled and prepared state to drm_panel not only doesn't align well with atomic state handling, but also would hide issues in upper layers that should really be fixed there. > Signed-off-by: Sam Ravnborg > Cc: Maarten Lankhorst > Cc: Maxime Ripard > Cc: Sean Paul > Cc: Thierry Reding > Cc: Sam Ravnborg > Cc: David Airlie > Cc: Daniel Vetter > --- > 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel