On Sat, Jun 01, 2024 at 08:24:59AM GMT, Adam Ford wrote:
> In the process of adding support for shared IRQ pins, a scenario
> was accidentally created where adv7511_irq_process returned
> prematurely causing the EDID to fail randomly.
>
> Since the interrupt handler is broken up into two main helper functions,
> update both of them to treat the helper functions as IRQ handlers. These
> IRQ routines process their respective tasks as before, but if they
> determine that actual work was done, mark the respective IRQ status
> accordingly, and delay the check until everything has been processed.
>
> This should guarantee the helper functions don't return prematurely
> while still returning proper values of either IRQ_HANDLED or IRQ_NONE.
>
> Reported-by: Liu Ying <victor....@nxp.com>
> Fixes: f3d9683346d6 ("drm/bridge: adv7511: Allow IRQ to share GPIO pins")
> Signed-off-by: Adam Ford <aford...@gmail.com>
> Tested-by: Liu Ying <victor....@nxp.com> # i.MX8MP EVK ADV7535 EDID retrieval
> w/o IRQ
> ---
> V2: Fix uninitialized cec_status
> Cut back a little on error handling to return either IRQ_NONE or
> IRQ_HANDLED.
>
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h
> b/drivers/gpu/drm/bridge/adv7511/adv7511.h
> index ea271f62b214..ec0b7f3d889c 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
> @@ -401,7 +401,7 @@ struct adv7511 {
>
> #ifdef CONFIG_DRM_I2C_ADV7511_CEC
> int adv7511_cec_init(struct device *dev, struct adv7511 *adv7511);
> -void adv7511_cec_irq_process(struct adv7511 *adv7511, unsigned int irq1);
> +int adv7511_cec_irq_process(struct adv7511 *adv7511, unsigned int irq1);
> #else
> static inline int adv7511_cec_init(struct device *dev, struct adv7511
> *adv7511)
> {
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_cec.c
> b/drivers/gpu/drm/bridge/adv7511/adv7511_cec.c
> index 44451a9658a3..651fb1dde780 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_cec.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_cec.c
> @@ -119,7 +119,7 @@ static void adv7511_cec_rx(struct adv7511 *adv7511, int
> rx_buf)
> cec_received_msg(adv7511->cec_adap, &msg);
> }
>
> -void adv7511_cec_irq_process(struct adv7511 *adv7511, unsigned int irq1)
> +int adv7511_cec_irq_process(struct adv7511 *adv7511, unsigned int irq1)
> {
> unsigned int offset = adv7511->info->reg_cec_offset;
> const u32 irq_tx_mask = ADV7511_INT1_CEC_TX_READY |
> @@ -130,17 +130,21 @@ void adv7511_cec_irq_process(struct adv7511 *adv7511,
> unsigned int irq1)
> ADV7511_INT1_CEC_RX_READY3;
> unsigned int rx_status;
> int rx_order[3] = { -1, -1, -1 };
> - int i;
> + int i, ret = 0;
> + int irq_status = IRQ_NONE;
>
> - if (irq1 & irq_tx_mask)
> + if (irq1 & irq_tx_mask) {
> adv_cec_tx_raw_status(adv7511, irq1);
> + irq_status = IRQ_HANDLED;
> + }
>
> if (!(irq1 & irq_rx_mask))
> - return;
> + return irq_status;
>
> - if (regmap_read(adv7511->regmap_cec,
> - ADV7511_REG_CEC_RX_STATUS + offset, &rx_status))
> - return;
> + ret = regmap_read(adv7511->regmap_cec,
> + ADV7511_REG_CEC_RX_STATUS + offset, &rx_status);
There is no need for the ret variable, regmap_read can return either 0
or a negative error code.
With that fixed:
Reviewed-by: Dmitry Baryshkov <dmitry.barysh...@linaro.org>
> + if (ret < 0)
> + return irq_status;
>
> /*
> * ADV7511_REG_CEC_RX_STATUS[5:0] contains the reception order of RX
--
With best wishes
Dmitry
