From: Ben Skeggs <bskeggs@redhat.com>
Date: Thu, 26 Aug 2010 05:02:32 +0000 (+1000)
Subject: drm/nouveau: drop drm_global_mutex before sleeping in submission path
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=ab699ec64a4294f2f6ccd34b9bf8a2dcb4c4cb3c;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git

drm/nouveau: drop drm_global_mutex before sleeping in submission path

If we keep hold of the mutex here, the process which currently holds the
buffer object will never be able to release it, causing a deadlock.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
---

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 613f878e6d0f..93711dfcafc1 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -337,7 +337,9 @@ retry:
 				return -EINVAL;
 			}
 
+			mutex_unlock(&drm_global_mutex);
 			ret = ttm_bo_wait_cpu(&nvbo->bo, false);
+			mutex_lock(&drm_global_mutex);
 			if (ret) {
 				NV_ERROR(dev, "fail wait_cpu\n");
 				return ret;