[PATCH v2 4/8] drm/i915: Disable framebuffer compression for i915 driver in VM

[Yu Zhang <yu.c.zhang@linux.intel.com>]

Framebuffer compression is disabled when driver detects it's
running in XenGT VM, because XenGT does not provide emulations
for FBC related operations, and we do not expose stolen memory
to the VM.

v2: 
take Chris' comments:
	- move the code into intel_update_fbc()

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Jike Song <jike.song@intel.com>
Signed-off-by: Zhiyuan Lv <zhiyuan.lv@intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index daa99e7..50cf96b 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -544,6 +544,10 @@ void intel_update_fbc(struct drm_device *dev)
 		return;
 	}
 
+	/* disable framebuffer compression in vgt */
+	if (intel_vgpu_active(dev))
+		i915.enable_fbc = 0;
+
 	/*
 	 * If FBC is already on, we just have to verify that we can
 	 * keep it that way...
-- 
1.9.1