Patch "drm/radeon: Poll for both connect/disconnect on analog connectors" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

drm/radeon: Poll for both connect/disconnect on analog connectors

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-radeon-poll-for-both-connect-disconnect-on-analog-connectors.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Lyude <[email protected]>
Date: Fri, 24 Jun 2016 17:54:31 -0400
Subject: drm/radeon: Poll for both connect/disconnect on analog connectors

From: Lyude <[email protected]>

commit 14ff8d48f2235295dfb3117693008e367b49cdb5 upstream.

DRM_CONNECTOR_POLL_CONNECT only enables polling for connections, not disconnections. Because of this, we end up losing hotplug polling for analog connectors once they get connected.

Easy way to reproduce:
- Grab a machine with a radeon GPU and a VGA port
- Plug a monitor into the VGA port, wait for it to update the connector from disconnected to connected
- Disconnect the monitor on VGA, a hotplug event is never sent for the removal of the connector.

Originally, only using DRM_CONNECTOR_POLL_CONNECT might have been a good idea since doing VGA polling can sometimes result in having to mess with the DAC voltages to figure out whether or not there's actually something there since VGA doesn't have HPD. Doing this would have the potential of showing visible artifacts on the screen every time we ran a poll while a VGA display was connected. Luckily, radeon_vga_detect() only resorts to this sort of polling if the poll is forced, and DRM's polling helper doesn't force it's polls.

Additionally, this removes some assignments to connector->polled that weren't actually doing anything.

---
 drivers/gpu/drm/radeon/radeon_connectors.c |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

@@ -2058,7 +2058,6 @@ radeon_add_atom_connector(struct drm_dev
 							   RADEON_OUTPUT_CSC_BYPASS);
 			/* no HPD on analog connectors */
 			radeon_connector->hpd.hpd = RADEON_HPD_NONE;
-			connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 			connector->interlace_allowed = true;
 			connector->doublescan_allowed = true;
 			break;

@@ -2308,8 +2307,10 @@ radeon_add_atom_connector(struct drm_dev
 	}
 
 	if (radeon_connector->hpd.hpd == RADEON_HPD_NONE) {
-		if (i2c_bus->valid)
-			connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+		if (i2c_bus->valid) {
+			connector->polled = DRM_CONNECTOR_POLL_CONNECT |
+			                    DRM_CONNECTOR_POLL_DISCONNECT;
+		}
 	} else
 		connector->polled = DRM_CONNECTOR_POLL_HPD;
 

@@ -2385,7 +2386,6 @@ radeon_add_legacy_connector(struct drm_d
 					      1);
 		/* no HPD on analog connectors */
 		radeon_connector->hpd.hpd = RADEON_HPD_NONE;
-		connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 		connector->interlace_allowed = true;
 		connector->doublescan_allowed = true;
 		break;

@@ -2470,10 +2470,13 @@ radeon_add_legacy_connector(struct drm_d
 	}
 
 	if (radeon_connector->hpd.hpd == RADEON_HPD_NONE) {
-		if (i2c_bus->valid)
-			connector->polled = DRM_CONNECTOR_POLL_CONNECT;
+		if (i2c_bus->valid) {
+			connector->polled = DRM_CONNECTOR_POLL_CONNECT |
+			                    DRM_CONNECTOR_POLL_DISCONNECT;
+		}
 	} else
 		connector->polled = DRM_CONNECTOR_POLL_HPD;
+
 	connector->display_info.subpixel_order = subpixel_order;
 	drm_connector_register(connector);
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/drm-amdgpu-poll-for-both-connect-disconnect-on-analog-connectors.patch queue-4.4/drm-radeon-poll-for-both-connect-disconnect-on-analog-connectors.patch queue-4.4/drm-amdgpu-disable-rpm-helpers-while-reprobing-connectors-on-resume.patch