All the panel driver check the fact that their prepare/unprepare
call was already called. It's not an ideal solution but fix
for now the problem on ili9881c
[ 9862.283296] ------------[ cut here ]------------
[ 9862.288490] unbalanced disables for vcc3v3_lcd
[ 9862.293555] WARNING: CPU: 0 PID: 1 at drivers/regulator/core.c:2851
_regulator_disable+0xd4/0x190
from:
[ 9862.038619] drm_panel_unprepare+0x2c/0x4c
[ 9862.043212] panel_bridge_post_disable+0x18/0x24
[ 9862.048390] dw_mipi_dsi_bridge_post_disable+0x3c/0xf0
[ 9862.054153] drm_atomic_bridge_chain_post_disable+0x8c/0xd0
and:
[ 9862.183103] drm_panel_unprepare+0x2c/0x4c
[ 9862.187695] panel_bridge_post_disable+0x18/0x24
[ 9862.192872] drm_atomic_bridge_chain_post_disable+0x8c/0xd0
[ 9862.199117] disable_outputs+0x120/0x31c
Signed-off-by: Michael Trimarchi <michael@xxxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/panel/panel-ilitek-ili9881c.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c b/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
index 103a16018975..f75eecb0e65c 100644
--- a/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
+++ b/drivers/gpu/drm/panel/panel-ilitek-ili9881c.c
@@ -52,6 +52,8 @@ struct ili9881c {
struct regulator *power;
struct gpio_desc *reset;
+
+ bool prepared;
};
#define ILI9881C_SWITCH_PAGE_INSTR(_page) \
@@ -707,6 +709,10 @@ static int ili9881c_prepare(struct drm_panel *panel)
unsigned int i;
int ret;
+ /* Preparing when already prepared is a no-op */
+ if (ctx->prepared)
+ return 0;
+
/* Power the panel */
ret = regulator_enable(ctx->power);
if (ret)
@@ -745,6 +751,8 @@ static int ili9881c_prepare(struct drm_panel *panel)
if (ret)
return ret;
+ ctx->prepared = true;
+
return 0;
}
@@ -770,10 +778,16 @@ static int ili9881c_unprepare(struct drm_panel *panel)
{
struct ili9881c *ctx = panel_to_ili9881c(panel);
+ /* Unpreparing when already unprepared is a no-op */
+ if (!ctx->prepared)
+ return 0;
+
mipi_dsi_dcs_enter_sleep_mode(ctx->dsi);
regulator_disable(ctx->power);
gpiod_set_value(ctx->reset, 1);
+ ctx->prepared = false;
+
return 0;
}
--
2.25.1
