Quoting Kuogee Hsieh (2021-01-07 12:30:25)
> There is HPD unplug interrupts missed at scenario of an irq_hpd
> followed by unplug interrupts with around 10 ms in between.
> Since both AUX_SW_RESET and DP_SW_RESET clear pending HPD interrupts,
> irq_hpd handler should not issues either aux or sw reset to avoid
> following unplug interrupt be cleared accidentally.
So the problem is that we're resetting the DP aux phy in the middle of
the HPD state machine transitioning states?
>
> Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
> ---
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
> index 44f0c57..9c0ce98 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
> @@ -190,6 +190,18 @@ int dp_catalog_aux_clear_hw_interrupts(struct dp_catalog *dp_catalog)
> return 0;
> }
>
> +/**
> + * dp_catalog_aux_reset() - reset AUX controller
> + *
> + * @aux: DP catalog structure
> + *
> + * return: void
> + *
> + * This function reset AUX controller
> + *
> + * NOTE: reset AUX controller will also clear any pending HPD related interrupts
> + *
> + */
> void dp_catalog_aux_reset(struct dp_catalog *dp_catalog)
> {
> u32 aux_ctrl;
> @@ -483,6 +495,18 @@ int dp_catalog_ctrl_set_pattern(struct dp_catalog *dp_catalog,
> return 0;
> }
>
> +/**
> + * dp_catalog_ctrl_reset() - reset DP controller
> + *
> + * @aux: DP catalog structure
It's called dp_catalog though.
> + *
> + * return: void
> + *
> + * This function reset DP controller
resets the
> + *
> + * NOTE: reset DP controller will also clear any pending HPD related interrupts
> + *
> + */
> void dp_catalog_ctrl_reset(struct dp_catalog *dp_catalog)
> {
> u32 sw_reset;
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index e3462f5..f96c415 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -1296,7 +1296,8 @@ static int dp_ctrl_setup_main_link(struct dp_ctrl_private *ctrl,
> * transitioned to PUSH_IDLE. In order to start transmitting
> * a link training pattern, we have to first do soft reset.
> */
> - dp_catalog_ctrl_reset(ctrl->catalog);
> + if (*training_step != DP_TRAINING_NONE)
Can we check for the positive value instead? i.e.
DP_TRAINING_1/DP_TRAINING_2
> + dp_catalog_ctrl_reset(ctrl->catalog);
>
> ret = dp_ctrl_link_train(ctrl, cr, training_step);
>
