Re: [Intel-gfx] [PATCH 1/2] drm: Add HPD state to drm_connector_oob_hotplug_event()

Imre Deak
2022-02-14T17:59:39Z

On Mon, Feb 07, 2022 at 08:43:27PM -0800, Bjorn Andersson wrote:
> In some implementations, such as the Qualcomm platforms, the display
> driver has no way to query the current HPD state and as such it's
> impossible to distinguish between disconnect and attention events.
>
> Add a parameter to drm_connector_oob_hotplug_event() to pass the HPD
> state.
>
> Also push the test for unchanged state in the displayport altmode driver
> into the i915 driver, to allow other drivers to act upon each update.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>
> Note that the Intel driver has only been compile tested with this patch.
>
> drivers/gpu/drm/drm_connector.c | 6 ++++--
> drivers/gpu/drm/i915/display/intel_dp.c | 14 +++++++++++---
> drivers/gpu/drm/i915/i915_drv.h | 3 +++
> drivers/usb/typec/altmodes/displayport.c | 9 ++-------
> include/drm/drm_connector.h | 5 +++--
> 5 files changed, 23 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index a50c82bc2b2f..ad7295597c0f 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -2825,6 +2825,7 @@ struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
> /**
> * drm_connector_oob_hotplug_event - Report out-of-band hotplug event to connector
> * @connector_fwnode: fwnode_handle to report the event on
> + * @hpd_state: number of data lanes available
> *
> * On some hardware a hotplug event notification may come from outside the display
> * driver / device. An example of this is some USB Type-C setups where the hardware
> @@ -2834,7 +2835,8 @@ struct drm_connector *drm_connector_find_by_fwnode(struct fwnode_handle *fwnode)
> * This function can be used to report these out-of-band events after obtaining
> * a drm_connector reference through calling drm_connector_find_by_fwnode().
> */
> -void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode)
> +void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
> + bool hpd_state)
> {
> struct drm_connector *connector;
>
> @@ -2843,7 +2845,7 @@ void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode)
> return;
>
> if (connector->funcs->oob_hotplug_event)
> - connector->funcs->oob_hotplug_event(connector);
> + connector->funcs->oob_hotplug_event(connector, hpd_state);
>
> drm_connector_put(connector);
> }
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 146b83916005..00520867d37b 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -4816,15 +4816,23 @@ static int intel_dp_connector_atomic_check(struct drm_connector *conn,
> return intel_modeset_synced_crtcs(state, conn);
> }
>
> -static void intel_dp_oob_hotplug_event(struct drm_connector *connector)
> +static void intel_dp_oob_hotplug_event(struct drm_connector *connector, bool hpd_state)
> {
> struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector));
> struct drm_i915_private *i915 = to_i915(connector->dev);
> + bool need_work = false;
>
> spin_lock_irq(&i915->irq_lock);
> - i915->hotplug.event_bits |= BIT(encoder->hpd_pin);
> + if (hpd_state != i915->hotplug.oob_hotplug_state) {

hpd_state is speific to the encoder (pin) so similarly to event_bits
oob_hotplug_state should be a bitmask as well.

> + i915->hotplug.event_bits |= BIT(encoder->hpd_pin);
> +
> + i915->hotplug.oob_hotplug_state = hpd_state;
> + need_work = true;
> + }
> spin_unlock_irq(&i915->irq_lock);
> - queue_delayed_work(system_wq, &i915->hotplug.hotplug_work, 0);
> +
> + if (need_work)
> + queue_delayed_work(system_wq, &i915->hotplug.hotplug_work, 0);
> }
>
> static const struct drm_connector_funcs intel_dp_connector_funcs = {
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 8c1706fd81f9..543ebf1cfcf4 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -149,6 +149,9 @@ struct i915_hotplug {
> /* Whether or not to count short HPD IRQs in HPD storms */
> u8 hpd_short_storm_enabled;
>
> + /* Last state reported by oob_hotplug_event */
> + bool oob_hotplug_state;
> +
> /*
> * if we get a HPD irq from DP and a HPD irq from non-DP
> * the non-DP HPD could block the workqueue on a mode config
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index c1d8c23baa39..a4596be4d34a 100644
> --- a/drivers/usb/typec/altmodes/displayport.c
> +++ b/drivers/usb/typec/altmodes/displayport.c
> @@ -59,7 +59,6 @@ struct dp_altmode {
> struct typec_displayport_data data;
>
> enum dp_state state;
> - bool hpd;
>
> struct mutex lock; /* device lock */
> struct work_struct work;
> @@ -143,10 +142,7 @@ static int dp_altmode_status_update(struct dp_altmode *dp)
> if (!ret)
> dp->state = DP_STATE_CONFIGURE;
> } else {
> - if (dp->hpd != hpd) {
> - drm_connector_oob_hotplug_event(dp->connector_fwnode);
> - dp->hpd = hpd;
> - }
> + drm_connector_oob_hotplug_event(dp->connector_fwnode, hpd);
> }
>
> return ret;
> @@ -573,8 +569,7 @@ void dp_altmode_remove(struct typec_altmode *alt)
> cancel_work_sync(&dp->work);
>
> if (dp->connector_fwnode) {
> - if (dp->hpd)
> - drm_connector_oob_hotplug_event(dp->connector_fwnode);
> + drm_connector_oob_hotplug_event(dp->connector_fwnode, false);
>
> fwnode_handle_put(dp->connector_fwnode);
> }
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 64cf5f88c05b..7c90b8eb2ace 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1141,7 +1141,7 @@ struct drm_connector_funcs {
> * This will get called when a hotplug-event for a drm-connector
> * has been received from a source outside the display driver / device.
> */
> - void (*oob_hotplug_event)(struct drm_connector *connector);
> + void (*oob_hotplug_event)(struct drm_connector *connector, bool hpd_state);
> };
>
> /**
> @@ -1742,7 +1742,8 @@ drm_connector_is_unregistered(struct drm_connector *connector)
> DRM_CONNECTOR_UNREGISTERED;
> }
>
> -void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode);
> +void drm_connector_oob_hotplug_event(struct fwnode_handle *connector_fwnode,
> + bool hpd_state);
> const char *drm_get_connector_type_name(unsigned int connector_type);
> const char *drm_get_connector_status_name(enum drm_connector_status status);
> const char *drm_get_subpixel_order_name(enum subpixel_order order);
> --
> 2.33.1
>