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, 12 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 83cb43a24768..a361bb9bc243 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -518,7 +518,6 @@ static int i915_drm_freeze(struct drm_device *dev)
 
 		flush_delayed_work(&dev_priv->rps.delayed_resume_work);
 
-		intel_runtime_pm_disable_interrupts(dev);
 
 		intel_suspend_gt_powersave(dev);
 
@@ -532,6 +531,9 @@ static int i915_drm_freeze(struct drm_device *dev)
 		}
 		drm_modeset_unlock_all(dev);
 
+		intel_dp_mst_suspend(dev);
+		intel_runtime_pm_disable_interrupts(dev);
+
 		intel_modeset_suspend_hw(dev);
 	}
 
@@ -646,6 +648,15 @@ static int __i915_drm_thaw(struct drm_device *dev, bool restore_gtt_mappings)
 
 		intel_modeset_init_hw(dev);
 
+		{
+			unsigned long irqflags;
+			spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
+			if (dev_priv->display.hpd_irq_setup)
+				dev_priv->display.hpd_irq_setup(dev);
+			spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
+		}
+
+		intel_dp_mst_resume(dev);
 		drm_modeset_lock_all(dev);
 		intel_modeset_setup_hw_state(dev, true);
 		drm_modeset_unlock_all(dev);