As usual these patches were extracted from the raspberry pi repo:

https://github.com/raspberrypi/linux/tree/rpi-4.4.y

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 81 insertions, 0 deletions

diff --git a/target/linux/brcm2708/patches-4.4/0287-drm-vc4-Fix-spurious-GPU-resets-due-to-BO-reuse.patch b/target/linux/brcm2708/patches-4.4/0287-drm-vc4-Fix-spurious-GPU-resets-due-to-BO-reuse.patch
new file mode 100644
index 0000000000..b9bd4932ba
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.4/0287-drm-vc4-Fix-spurious-GPU-resets-due-to-BO-reuse.patch
@@ -0,0 +1,81 @@
+From 6fde872f91f4ff8dcf1b2c2017c04e4f1dee07f7 Mon Sep 17 00:00:00 2001
+From: Eric Anholt <eric@anholt.net>
+Date: Mon, 8 Feb 2016 11:19:14 -0800
+Subject: [PATCH 287/304] drm/vc4: Fix spurious GPU resets due to BO reuse.
+
+We were tracking the "where are the head pointers pointing" globally,
+so if another job reused the same BOs and execution was at the same
+point as last time we checked, we'd stop and trigger a reset even
+though the GPU had made progress.
+
+Signed-off-by: Eric Anholt <eric@anholt.net>
+(cherry picked from commit c4ce60dc30912df09b2438f1e5594eae1ef64d1e)
+---
+ drivers/gpu/drm/vc4/vc4_drv.h |  6 +++++-
+ drivers/gpu/drm/vc4/vc4_gem.c | 19 ++++++++++++++-----
+ 2 files changed, 19 insertions(+), 6 deletions(-)
+
+--- a/drivers/gpu/drm/vc4/vc4_drv.h
++++ b/drivers/gpu/drm/vc4/vc4_drv.h
+@@ -93,7 +93,6 @@ struct vc4_dev {
+ 	struct work_struct overflow_mem_work;
+ 
+ 	struct {
+-		uint32_t last_ct0ca, last_ct1ca;
+ 		struct timer_list timer;
+ 		struct work_struct reset_work;
+ 	} hangcheck;
+@@ -203,6 +202,11 @@ struct vc4_exec_info {
+ 	/* Sequence number for this bin/render job. */
+ 	uint64_t seqno;
+ 
++	/* Last current addresses the hardware was processing when the
++	 * hangcheck timer checked on us.
++	 */
++	uint32_t last_ct0ca, last_ct1ca;
++
+ 	/* Kernel-space copy of the ioctl arguments */
+ 	struct drm_vc4_submit_cl *args;
+ 
+--- a/drivers/gpu/drm/vc4/vc4_gem.c
++++ b/drivers/gpu/drm/vc4/vc4_gem.c
+@@ -271,10 +271,17 @@ vc4_hangcheck_elapsed(unsigned long data
+ 	struct drm_device *dev = (struct drm_device *)data;
+ 	struct vc4_dev *vc4 = to_vc4_dev(dev);
+ 	uint32_t ct0ca, ct1ca;
++	unsigned long irqflags;
++	struct vc4_exec_info *exec;
++
++	spin_lock_irqsave(&vc4->job_lock, irqflags);
++	exec = vc4_first_job(vc4);
+ 
+ 	/* If idle, we can stop watching for hangs. */
+-	if (list_empty(&vc4->job_list))
++	if (!exec) {
++		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
+ 		return;
++	}
+ 
+ 	ct0ca = V3D_READ(V3D_CTNCA(0));
+ 	ct1ca = V3D_READ(V3D_CTNCA(1));
+@@ -282,14 +289,16 @@ vc4_hangcheck_elapsed(unsigned long data
+ 	/* If we've made any progress in execution, rearm the timer
+ 	 * and wait.
+ 	 */
+-	if (ct0ca != vc4->hangcheck.last_ct0ca ||
+-	    ct1ca != vc4->hangcheck.last_ct1ca) {
+-		vc4->hangcheck.last_ct0ca = ct0ca;
+-		vc4->hangcheck.last_ct1ca = ct1ca;
++	if (ct0ca != exec->last_ct0ca || ct1ca != exec->last_ct1ca) {
++		exec->last_ct0ca = ct0ca;
++		exec->last_ct1ca = ct1ca;
++		spin_unlock_irqrestore(&vc4->job_lock, irqflags);
+ 		vc4_queue_hangcheck(dev);
+ 		return;
+ 	}
+ 
++	spin_unlock_irqrestore(&vc4->job_lock, irqflags);
++
+ 	/* We've gone too long with no progress, reset.  This has to
+ 	 * be done from a work struct, since resetting can sleep and
+ 	 * this timer hook isn't allowed to.