On Thu, 2019-04-11 at 17:36 +0300, Gwan-gyeong Mun wrote:
> The hotplug detection routine of drm_helper_hpd_irq_event() can
> detect
> changing of status of connector, but it can not detect changing of
> edid.
>
> Following scenario requires detection of changing of edid.
>
> 1) plug display device to a connector
> 2) system suspend
> 3) unplug 1)'s display device and plug the other display device to a
> connector
> 4) system resume
>
> It adds edid check routine when a connector status still remains as
> "connector_status_connected".
>
> v2: Add NULL check before comparing of EDIDs.
> v3: Make it as part of existing drm_helper_hpd_irq_event() (Stan,
> Mika)
> v4: Rebased
> v5: Use a cached edid property blob data of connector instead of
> adding
> a new detected_edid variable. (Maarten)
> Add an using of reference count for getting a cached edid
> property
> blob data. (Maarten)
>
> Testcase: igt/kms_chamelium/hdmi-edid-change-during-hibernate
> Testcase: igt/kms_chamelium/hdmi-edid-change-during-suspend
> Testcase: igt/kms_chamelium/dp-edid-change-during-hibernate
> Testcase: igt/kms_chamelium/dp-edid-change-during-suspend
>
> Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_probe_helper.c | 34
> +++++++++++++++++++++++++++++-
> 1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_probe_helper.c
> b/drivers/gpu/drm/drm_probe_helper.c
> index 6fd08e04b323..27ad7f3dabb7 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -742,7 +742,16 @@ EXPORT_SYMBOL(drm_kms_helper_poll_fini);
> * panels.
> *
> * This helper function is useful for drivers which can't or don't
> track hotplug
> - * interrupts for each connector.
> + * interrupts for each connector. And it also supports a detection
> of changing
> + * of edid on between suspend and resume when a connector status
> still remains
> + * as "connector_status_connected".
> + *
> + * Following scenario requires detection of changing of edid.
> + * 1) plug display device to a connector
> + * 2) system suspend
> + * 3) unplug 1)'s display device and plug the other display device
> to a
> + * connector
> + * 4) system resume
> *
> * Drivers which support hotplug interrupts for each connector
> individually and
> * which have a more fine-grained detect logic should bypass this
> code and
> @@ -760,6 +769,7 @@ bool drm_helper_hpd_irq_event(struct drm_device
> *dev)
> struct drm_connector *connector;
> struct drm_connector_list_iter conn_iter;
> enum drm_connector_status old_status;
> + struct drm_property_blob *old_edid_blob_ptr;
> bool changed = false;
>
> if (!dev->mode_config.poll_enabled)
> @@ -774,6 +784,11 @@ bool drm_helper_hpd_irq_event(struct drm_device
> *dev)
>
> old_status = connector->status;
>
> + if (connector->edid_blob_ptr)
> + old_edid_blob_ptr =
> drm_property_blob_get(connector->edid_blob_ptr);
> + else
> + old_edid_blob_ptr = NULL;
> +
> connector->status = drm_helper_probe_detect(connector,
> NULL, false);
> DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s
> to %s\n",
> connector->base.id,
> @@ -782,6 +797,23 @@ bool drm_helper_hpd_irq_event(struct drm_device
> *dev)
> drm_get_connector_status_name(connector-
> >status));
> if (old_status != connector->status)
> changed = true;
> +
> + /* Check changing of edid when a connector status still
> remains
> + * as "connector_status_connected".
> + */
> + if (old_edid_blob_ptr && connector->edid_blob_ptr &&
I guess you don't need to check both old_edid_blob_ptr && connector-
>edid_blob_ptr here. Because if old_edid_blob_ptr is not NULL - it
means that connector->edid_blob_ptr was not NULL for sure. See the
condition you have added above.
I mean this one:
> + if (connector->edid_blob_ptr)
> + old_edid_blob_ptr =
> drm_property_blob_get(connector->edid_blob_ptr);
> + else
> + old_edid_blob_ptr = NULL;
So I would check only old_edid_blob_ptr for not being NULL here.
> + old_status == connector->status &&
> + old_status == connector_status_connected) {
> + if (memcmp(old_edid_blob_ptr->data,
> + connector->edid_blob_ptr->data,
> + old_edid_blob_ptr->length)) {
> + changed = true;
> + DRM_DEBUG_KMS("[CONNECTOR:%d:%s] edid
> updated\n",
> + connector->base.id,
> + connector->name);
> + }
> + }
> + drm_property_blob_put(old_edid_blob_ptr);
> }
> drm_connector_list_iter_end(&conn_iter);
> mutex_unlock(&dev->mode_config.mutex);
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