drm/i915: add DP 1.2 MST support (v0.7)

This adds DP 1.2 MST support on Haswell systems.

Notes:
a) this reworks irq handling for DP MST ports, so that we can
avoid the mode config locking in the current hpd handlers, as
we need to process up/down msgs at a better time.

Changes since v0.1:
use PORT_PCH_HOTPLUG to detect short vs long pulses
add a workqueue to deal with digital events as they can get blocked on the
main workqueue beyong mode_config mutex
fix a bunch of modeset checker warnings
acks irqs in the driver
cleanup the MST encoders

Changes since v0.2:
check irq status again in work handler
move around bring up and tear down to fix DPMS on/off
use path properties.

Changes since v0.3:
updates for mst apis
more state checker fixes
irq handling improvements
fbcon handling support
improved reference counting of link - fixes redocking.

Changes since v0.4:
handle gpu reset hpd reinit without oopsing
check link status on HPD irqs
fix suspend/resume

Changes since v0.5:
use proper functions to get max link/lane counts
fix another checker backtrace - due to connectors disappearing.
set output type in more places fro, unknown->displayport
don't talk to devices if no HPD asserted
check mst on short irqs only
check link status properly
rebase onto prepping irq changes.
drop unsued force_act

Changes since v0.6:
cleanup unused struct entry.

[airlied: fix some sparse warnings].

Reviewed-by: Todd Previte <tprevite@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 6df6506db919..d335c46ec6bc 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1717,6 +1717,13 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 		goto out_mtrrfree;
 	}
 
+	dev_priv->dp_wq = alloc_ordered_workqueue("i915-dp", 0);
+	if (dev_priv->dp_wq == NULL) {
+		DRM_ERROR("Failed to create our dp workqueue.\n");
+		ret = -ENOMEM;
+		goto out_freewq;
+	}
+
 	intel_irq_init(dev);
 	intel_uncore_sanitize(dev);
 
@@ -1792,6 +1799,8 @@ out_gem_unload:
 	intel_teardown_gmbus(dev);
 	intel_teardown_mchbar(dev);
 	pm_qos_remove_request(&dev_priv->pm_qos);
+	destroy_workqueue(dev_priv->dp_wq);
+out_freewq:
 	destroy_workqueue(dev_priv->wq);
 out_mtrrfree:
 	arch_phys_wc_del(dev_priv->gtt.mtrr);
@@ -1892,6 +1901,7 @@ int i915_driver_unload(struct drm_device *dev)
 	intel_teardown_gmbus(dev);
 	intel_teardown_mchbar(dev);
 
+	destroy_workqueue(dev_priv->dp_wq);
 	destroy_workqueue(dev_priv->wq);
 	pm_qos_remove_request(&dev_priv->pm_qos);