Hi all
On Sat, Oct 16, 2021 at 4:58 PM Michael Trimarchi
<michael@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> 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;
> };
>
I found that this can be a general problem. Should not mandatory to
track panel status
DRM_PANEL_PREPARED
DRM_PANEL_ENABLED
Michael
> #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
>
--
Michael Nazzareno Trimarchi
Co-Founder & Chief Executive Officer
M. +39 347 913 2170
michael@xxxxxxxxxxxxxxxxxxxx
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