I will be taking over this series from Marius Vlad. This series addresses a shortcoming whereby a hot plug event is sent without it being passed the actual connector that caused it. This takes into consideration both the polling path and the HPD (Hot Plug Detect) path. It also adds support for the vkms driver (using ConfigFS) for propagating the connector ID when changing the connector's status.
The motivation is that user-space applications such as Weston would previously receive non-connector-specific hotplug events, and then have to figure out themselves which connector needs to have a modeset executed on. This notably did not work when the hotplug events came in too fast, resulting in Weston missing an on-off-on transition of a connector, seeing that its state was unchanged from "on" so can't be the one that was hotplugged, and skipping reinitialising it as it looks through the other connectors that could've caused it. The real world implication is that on setups with slightly sketchy HDMI connections, a brief flicker in the HPD signal could result in video output bidding farewell entirely until a manual proper re-plug was performed. By sending connector specific hotplug events, this ambiguity is resolved without any change to the user-space API. Signed-off-by: Nicolas Frattaroli <[email protected]> --- Changes in v6: - Rewrote cover letter to explain the motivation for this series more plainly - Rename "status_changed" to "pending_hp" - Set "pending_hp" in the existing path that would also affect epoch_counter - No longer set the boolean in drm_helper_probe_single_connector_modes, as it does not appear to be necessary - Reword commits to better justify the changes - Link to v5: https://lore.kernel.org/r/[email protected]/ Changes in v5: - vkms: add support for sending the CONNECTOR ID when hot-plugging through ConfigFS - as reported by Louis, vkms can now make use of ConfigFS to simulate connector status. - vkms: add a small change to ignore previous/old drm connector status when sending out hot-plug uevent. - Link to v4: https://lore.kernel.org/r/[email protected]/ Changes in v4: - removed the "This patch" bit - Dmitry - added a short note when the flag is set and cleared - Dmitry - address double dead-locking detected - kbot: https://lore.kernel.org/dri-devel/[email protected]/ - virtual connectors do not seem have any kind of hotplug - added polling in vkms - as noted by Ian - Link to v3: https://lore.kernel.org/r/[email protected]/ Changes in v3: - Address comments from Dmitry: - guard connector status write with mode_config.mutex - avoid setting up the connector status and immediately unset it. Do the unset in drm_kms_helper_hotplug_event/drm_kms_helper_connector_hotplug_event - Link to v2: https://lore.kernel.org/r/[email protected]/ Changes in v2: - Address comments from Daniel: - split patch into 2, one that introduces a bool to track connector connection status change and a patch that uses that to be able to send hot plug events with the proper CONNECTOR ID to udev and further pass that down to user-space - nuke out mutex when iterating connector list - fix typo - Link to v1: https://lore.kernel.org/r/[email protected]/ Marius Vlad (4): drm: Introduce a new connector status drm: Propagate connector status change vkms: Do not send hotplug events for same connector status vkms: Pass the vkms connector as opposed to the vkms device drivers/gpu/drm/drm_connector.c | 1 + drivers/gpu/drm/drm_probe_helper.c | 39 +++++++++++++++++++++++---- drivers/gpu/drm/drm_sysfs.c | 1 + drivers/gpu/drm/vkms/vkms_configfs.c | 12 +++++++-- drivers/gpu/drm/vkms/vkms_connector.c | 6 ++--- drivers/gpu/drm/vkms/vkms_connector.h | 4 +-- include/drm/drm_connector.h | 3 +++ 7 files changed, 54 insertions(+), 12 deletions(-) -- 2.47.2 --- Marius Vlad (4): drm: Introduce pending_hp to drm_connector drm: Send per-connector hotplug events vkms: Do not send hotplug events for same connector status vkms: Pass the vkms connector as opposed to the device on hotplug drivers/gpu/drm/drm_connector.c | 1 + drivers/gpu/drm/drm_probe_helper.c | 39 ++++++++++++++++++++++++++++++----- drivers/gpu/drm/drm_sysfs.c | 2 ++ drivers/gpu/drm/vkms/vkms_configfs.c | 6 ++++-- drivers/gpu/drm/vkms/vkms_connector.c | 6 +++--- drivers/gpu/drm/vkms/vkms_connector.h | 4 ++-- include/drm/drm_connector.h | 3 +++ 7 files changed, 49 insertions(+), 12 deletions(-) --- base-commit: ab42b1c3fe4ce1ae5534c51b880d3a97e6bba145 change-id: 20260121-hot-plug-passup-f8ed03f7c202 Best regards, -- Nicolas Frattaroli <[email protected]>
