[PATCH] drm/vmwgfx: Fix a command submission hang regression

[Thomas Hellstrom]

When we're out of command buffer space, we turn on the command buffer
processed irq without re-checking for finished command buffers afterwards.
This might lead to a missed irq and the command submission process waiting
forever for space.

Fix this by rerunning the command buffer submission handler whenever we're
out of command space. This ensures both that we don't needlessly turn on
the irq, and that if we decide to turn on the irq, we recheck for finished
command buffers before going to sleep.

Reported-and-tested-by: Bryan Li <ldexin at vmware.com>
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Sinclair Yeh <syeh at vmware.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c
index 5ae8f92..8a76821 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_cmdbuf.c
@@ -681,6 +681,14 @@ static bool vmw_cmdbuf_try_alloc(struct vmw_cmdbuf_man *man,
 					 0, 0,
 					 DRM_MM_SEARCH_DEFAULT,
 					 DRM_MM_CREATE_DEFAULT);
+	if (ret) {
+		(void) vmw_cmdbuf_man_process(man);
+		ret = drm_mm_insert_node_generic(&man->mm, info->node,
+						 info->page_size, 0, 0,
+						 DRM_MM_SEARCH_DEFAULT,
+						 DRM_MM_CREATE_DEFAULT);
+	}
+
 	spin_unlock_bh(&man->lock);
 	info->done = !ret;
 
-- 
2.1.0