[3.16.y-ckt stable] Patch "drm/i915: Dont enable CS_PARSER_ERROR interrupts at all" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    drm/i915: Dont enable CS_PARSER_ERROR interrupts at all

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From f2871754b5f5e2696d963e7ccfd52a2c7cf57c39 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter at ffwll.ch>
Date: Wed, 1 Apr 2015 13:43:46 +0200
Subject: drm/i915: Dont enable CS_PARSER_ERROR interrupts at all

commit 37ef01ab5d24d1d520dc79f6a98099d451c2a901 upstream.

We stopped handling them in

commit aaecdf611a05cac26a94713bad25297e60225c29
Author: Daniel Vetter <daniel.vetter at ffwll.ch>
Date:   Tue Nov 4 15:52:22 2014 +0100

    drm/i915: Stop gathering error states for CS error interrupts

but just clearing is apparently not enough: A sufficiently dead gpu
left behind by firmware (*cough* coreboot *cough*) can keep the gpu in
an endless loop of such interrupts, eventually leading to the nmi
firing. And definitely to what looks like a machine hang.

Since we don't even enable these interrupts on gen5+ let's do the same
on earlier platforms.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=93171
Tested-by: Mono <mono-for-kernel-org at donderklumpen.de>
Tested-by: info at gluglug.org.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 085cb5645e66..a736b4af46f1 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3687,14 +3687,12 @@ static int i8xx_irq_postinstall(struct drm_device *dev)
 		~(I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
 		  I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
 		  I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
-		  I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT |
-		  I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT);
+		  I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT);
 	I915_WRITE16(IMR, dev_priv->irq_mask);

 	I915_WRITE16(IER,
 		     I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
 		     I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
-		     I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT |
 		     I915_USER_INTERRUPT);
 	POSTING_READ16(IER);

@@ -3856,14 +3854,12 @@ static int i915_irq_postinstall(struct drm_device *dev)
 		  I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
 		  I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
 		  I915_DISPLAY_PLANE_A_FLIP_PENDING_INTERRUPT |
-		  I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT |
-		  I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT);
+		  I915_DISPLAY_PLANE_B_FLIP_PENDING_INTERRUPT);

 	enable_mask =
 		I915_ASLE_INTERRUPT |
 		I915_DISPLAY_PIPE_A_EVENT_INTERRUPT |
 		I915_DISPLAY_PIPE_B_EVENT_INTERRUPT |
-		I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT |
 		I915_USER_INTERRUPT;

 	if (I915_HAS_HOTPLUG(dev)) {