On 5/16/23 10:12, Jagan Teki wrote:
Hi Marek and Neil,
On Sun, May 14, 2023 at 1:40 AM Marek Vasut <[email protected]> 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 <[email protected]>
---
Cc: Andrzej Hajda <[email protected]>
Cc: Antonio Borneo <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Jernej Skrabec <[email protected]>
Cc: Jonas Karlman <[email protected]>
Cc: Laurent Pinchart <[email protected]>
Cc: Marek Vasut <[email protected]>
Cc: Neil Armstrong <[email protected]>
Cc: Philipp Zabel <[email protected]>
Cc: Philippe Cornu <[email protected]>
Cc: Robert Foss <[email protected]>
Cc: Vincent Abriou <[email protected]>
Cc: Yannick Fertre <[email protected]>
Cc: [email protected]
---
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.
Did I miss a panel_bridge pre_enable call somewhere in the driver ?
Where is it ?
