Patch "drm/i915/skl: Fix spurious gpu hang with gt3/gt4 revs" has been added to the 4.5-stable tree

[<gregkh@linuxfoundation.org>]

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

    drm/i915/skl: Fix spurious gpu hang with gt3/gt4 revs

to the 4.5-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-i915-skl-fix-spurious-gpu-hang-with-gt3-gt4-revs.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 510650e8b2ab965931b35e9813467439d4df0b9c Mon Sep 17 00:00:00 2001
From: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date: Tue, 5 Apr 2016 15:56:17 +0300
Subject: drm/i915/skl: Fix spurious gpu hang with gt3/gt4 revs

From: Mika Kuoppala <mika.kuoppala@linux.intel.com>

commit 510650e8b2ab965931b35e9813467439d4df0b9c upstream.

Experiments with heaven 4.0 benchmark and skylake gt3e (rev 0xa)
suggest that WaForceContextSaveRestoreNonCoherent is needed for all
revs. Extending this to all revs cures a gpu hang with rev 0xa when
running heaven4.0 gpu benchmark.

We have been here before, with problems enabling gt4e and extending
up to revision F0 instead of false claims of bspec of E0 only. See
commit <e238659ddd88> ("drm/i915/skl: Default to noncoherent access
up to F0"). In retrospect we should have covered this with this big
blanket back then already, as E0 vs F0 discrepancy was suspicious
enough.

Previously the WaForceEnableNonCoherent has been tied to
context non-coherence, atleast in relevant hsds. So keep this tie
and extended this alongside.

Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Timo Aaltonen <tjaalton@ubuntu.com>
Reported-by: Mike Lothian <mike@fireburn.co.uk>
References: https://bugs.freedesktop.org/show_bug.cgi?id=93491
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Ben Widawsky <benjamin.widawsky@intel.com>
Tested-by: Timo Aaltonen <tjaalton@ubuntu.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459860977-27751-2-git-send-email-mika.kuoppala@intel.com
(cherry picked from commit 97ea6be161c55dec896b65c95157d953c330ae05)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/i915/intel_ringbuffer.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -951,7 +951,7 @@ static int gen9_init_workarounds(struct
 
 	/* WaForceContextSaveRestoreNonCoherent:skl,bxt */
 	tmp = HDC_FORCE_CONTEXT_SAVE_RESTORE_NON_COHERENT;
-	if (IS_SKL_REVID(dev, SKL_REVID_F0, SKL_REVID_F0) ||
+	if (IS_SKL_REVID(dev, SKL_REVID_F0, REVID_FOREVER) ||
 	    IS_BXT_REVID(dev, BXT_REVID_B0, REVID_FOREVER))
 		tmp |= HDC_FORCE_CSR_NON_COHERENT_OVR_DISABLE;
 	WA_SET_BIT_MASKED(HDC_CHICKEN0, tmp);
@@ -1044,7 +1044,8 @@ static int skl_init_workarounds(struct i
 		WA_SET_BIT_MASKED(HIZ_CHICKEN,
 				  BDW_HIZ_POWER_COMPILER_CLOCK_GATING_DISABLE);
 
-	if (IS_SKL_REVID(dev, 0, SKL_REVID_F0)) {
+	/* This is tied to WaForceContextSaveRestoreNonCoherent */
+	if (IS_SKL_REVID(dev, 0, REVID_FOREVER)) {
 		/*
 		 *Use Force Non-Coherent whenever executing a 3D context. This
 		 * is a workaround for a possible hang in the unlikely event


Patches currently in stable-queue which might be from mika.kuoppala@linux.intel.com are

queue-4.5/drm-i915-use-fw_domains_put_with_fifo-on-hsw.patch
queue-4.5/drm-i915-skl-fix-spurious-gpu-hang-with-gt3-gt4-revs.patch