From 965198c509d5b0d5d69db614c631b695f97979cc Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Sun, 2 Dec 2012 14:49:44 +0100
Subject: [PATCH] --- yaml --- r: 357949 b: refs/heads/master c:
 59ad1465423d968f06f243bc52cc3b1a320a27cf h: refs/heads/master i:   357947:
 6815e10b739324cfc53a23664a1a7c4c6be5e536 v: v3

---
 [refs]                                       |  2 +-
 trunk/drivers/gpu/drm/nouveau/nv50_display.c | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index f5d4454075fb..5d73358ac72a 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7147573a5ce499dec3979e6b524691d47e1288d5
+refs/heads/master: 59ad1465423d968f06f243bc52cc3b1a320a27cf
diff --git a/trunk/drivers/gpu/drm/nouveau/nv50_display.c b/trunk/drivers/gpu/drm/nouveau/nv50_display.c
index 35874085a61e..d4cbea19b890 100644
--- a/trunk/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/trunk/drivers/gpu/drm/nouveau/nv50_display.c
@@ -128,6 +128,11 @@ struct nv50_dmac {
 	struct nv50_chan base;
 	dma_addr_t handle;
 	u32 *ptr;
+
+	/* Protects against concurrent pushbuf access to this channel, lock is
+	 * grabbed by evo_wait (if the pushbuf reservation is successful) and
+	 * dropped again by evo_kick. */
+	struct mutex lock;
 };
 
 static void
@@ -271,6 +276,8 @@ nv50_dmac_create(struct nouveau_object *core, u32 bclass, u8 head,
 	u32 pushbuf = *(u32 *)data;
 	int ret;
 
+	mutex_init(&dmac->lock);
+
 	dmac->ptr = pci_alloc_consistent(nv_device(core)->pdev, PAGE_SIZE,
 					&dmac->handle);
 	if (!dmac->ptr)
@@ -395,11 +402,13 @@ evo_wait(void *evoc, int nr)
 	struct nv50_dmac *dmac = evoc;
 	u32 put = nv_ro32(dmac->base.user, 0x0000) / 4;
 
+	mutex_lock(&dmac->lock);
 	if (put + nr >= (PAGE_SIZE / 4) - 8) {
 		dmac->ptr[put] = 0x20000000;
 
 		nv_wo32(dmac->base.user, 0x0000, 0x00000000);
 		if (!nv_wait(dmac->base.user, 0x0004, ~0, 0x00000000)) {
+			mutex_unlock(&dmac->lock);
 			NV_ERROR(dmac->base.user, "channel stalled\n");
 			return NULL;
 		}
@@ -415,6 +424,7 @@ evo_kick(u32 *push, void *evoc)
 {
 	struct nv50_dmac *dmac = evoc;
 	nv_wo32(dmac->base.user, 0x0000, (push - dmac->ptr) << 2);
+	mutex_unlock(&dmac->lock);
 }
 
 #define evo_mthd(p,m,s) *((p)++) = (((s) << 18) | (m))