Hi Marek and Neil, On Sun, May 14, 2023 at 1:40 AM Marek Vasut <ma...@denx.de> wrote: > > This panel_bridge post_disable callback is called from the bridge chain now, > so drop the explicit call here. This fixes call imbalance, where this driver > does not call ->pre_enable, but does call ->post_disable . In case either of > the two callbacks implemented in one of the panel or bridge drivers contains > any operation with refcounted object, like regulator, this would make kernel > complain about the imbalance. > > This can be triggered e.g. with ST7701 driver, which operates on regulators > in its prepare/unprepare callbacks, which are called from > pre_enable/post_disable > callbacks respectively. The former is called once, the later twice, during > entry to suspend. > > Drop the post_disable call to fix the imbalance. > > Signed-off-by: Marek Vasut <ma...@denx.de> > --- > Cc: Andrzej Hajda <andrzej.ha...@intel.com> > Cc: Antonio Borneo <antonio.bor...@foss.st.com> > Cc: Daniel Vetter <dan...@ffwll.ch> > Cc: David Airlie <airl...@gmail.com> > Cc: Jernej Skrabec <jernej.skra...@gmail.com> > Cc: Jonas Karlman <jo...@kwiboo.se> > Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com> > Cc: Marek Vasut <ma...@denx.de> > Cc: Neil Armstrong <neil.armstr...@linaro.org> > Cc: Philipp Zabel <p.za...@pengutronix.de> > Cc: Philippe Cornu <philippe.co...@foss.st.com> > Cc: Robert Foss <robert.f...@linaro.org> > Cc: Vincent Abriou <vincent.abr...@st.com> > Cc: Yannick Fertre <yannick.fer...@foss.st.com> > Cc: dri-devel@lists.freedesktop.org > --- > drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 9 --------- > 1 file changed, 9 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > index b2efecf7d1603..63ac972547361 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c > @@ -859,15 +859,6 @@ static void > dw_mipi_dsi_bridge_post_atomic_disable(struct drm_bridge *bridge, > */ > dw_mipi_dsi_set_mode(dsi, 0); > > - /* > - * TODO Only way found to call panel-bridge post_disable & > - * panel unprepare before the dsi "final" disable... > - * This needs to be fixed in the drm_bridge framework and the API > - * needs to be updated to manage our own call chains... > - */ > - if (dsi->panel_bridge->funcs->post_disable) > - dsi->panel_bridge->funcs->post_disable(dsi->panel_bridge); > -
If my understanding was correct, the controller set the low-speed DCS in pre_enable and high-speed DCS in enable. So I'm thinking this explicit post_disable still needs to revert the operation within the bridge chain. I didn't test this but trying to understand how the existing behaviour is satisfied if we drop this. Thanks, Jagan.
