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path: root/patches/drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch
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From: Mike Galbraith <umgwanakikbuti@gmail.com>
Date: Sat, 27 Feb 2016 09:01:42 +0100
Subject: [PATCH] drm/i915: Don't disable interrupts on PREEMPT_RT during
 atomic updates

Commit
   8d7849db3eab7 ("drm/i915: Make sprite updates atomic")

started disabling interrupts across atomic updates. This breaks on PREEMPT_RT
because within this section the code attempt to acquire spinlock_t locks which
are sleeping locks on PREEMPT_RT.

According to the comment the interrupts are disabled to avoid random delays and
not required for protection or synchronisation.

Don't disable interrupts on PREEMPT_RT during atomic updates.

[bigeasy: drop local locks, commit message]

Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/gpu/drm/i915/display/intel_sprite.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/i915/display/intel_sprite.c
+++ b/drivers/gpu/drm/i915/display/intel_sprite.c
@@ -118,7 +118,8 @@ void intel_pipe_update_start(const struc
 			"PSR idle timed out 0x%x, atomic update may fail\n",
 			psr_status);
 
-	local_irq_disable();
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		local_irq_disable();
 
 	crtc->debug.min_vbl = min;
 	crtc->debug.max_vbl = max;
@@ -143,11 +144,13 @@ void intel_pipe_update_start(const struc
 			break;
 		}
 
-		local_irq_enable();
+		if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+			local_irq_enable();
 
 		timeout = schedule_timeout(timeout);
 
-		local_irq_disable();
+		if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+			local_irq_disable();
 	}
 
 	finish_wait(wq, &wait);
@@ -180,7 +183,8 @@ void intel_pipe_update_start(const struc
 	return;
 
 irq_disable:
-	local_irq_disable();
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		local_irq_disable();
 }
 
 /**
@@ -218,7 +222,8 @@ void intel_pipe_update_end(struct intel_
 		new_crtc_state->uapi.event = NULL;
 	}
 
-	local_irq_enable();
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		local_irq_enable();
 
 	if (intel_vgpu_active(dev_priv))
 		return;