drm/i915: Fix reason for per-chip disabling of FBC

When running on my snb machine, recent kernels display successively:

[drm:intel_update_fbc], fbc set to per-chip default
[drm:intel_update_fbc], fbc disabled per module param

But no module param is set. This happens because the check for the
module parameter uses a variable that has been overridden inside the
"per-chip default" code.

Fix up the logic and add another reason for the FBC to the be disabled.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

3 files changed, 10 insertions, 8 deletions

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 47d6c748057e..dca49828e3fc 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1518,6 +1518,9 @@ static int i915_fbc_status(struct seq_file *m, void *unused)
                 case FBC_MODULE_PARAM:
                         seq_printf(m, "disabled per module param (default off)");
                         break;
+                case FBC_CHIP_DEFAULT:
+                        seq_printf(m, "disabled per chip default");
+                        break;
                 default:
                         seq_printf(m, "unknown reason");
                 }
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index cc1d6056ab70..59c45f293ec9 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -537,6 +537,7 @@ enum no_fbc_reason {
         FBC_NOT_TILED, /* buffer not tiled */
         FBC_MULTIPLE_PIPES, /* more than one pipe active */
         FBC_MODULE_PARAM,
+        FBC_CHIP_DEFAULT, /* disabled by default on this chip */
 };
 
 enum intel_pch {
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index e0de8b3337d8..adc7f3eb4ef3 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -447,7 +447,6 @@ void intel_update_fbc(struct drm_device *dev)
         struct drm_framebuffer *fb;
         struct intel_framebuffer *intel_fb;
         struct drm_i915_gem_object *obj;
-        int enable_fbc;
         unsigned int max_hdisplay, max_vdisplay;
 
         if (!i915_powersave)
@@ -488,14 +487,13 @@ void intel_update_fbc(struct drm_device *dev)
         intel_fb = to_intel_framebuffer(fb);
         obj = intel_fb->obj;
 
-        enable_fbc = i915_enable_fbc;
-        if (enable_fbc < 0) {
-                DRM_DEBUG_KMS("fbc set to per-chip default\n");
-                enable_fbc = 1;
-                if (INTEL_INFO(dev)->gen <= 7 && !IS_HASWELL(dev))
-                        enable_fbc = 0;
+        if (i915_enable_fbc < 0 &&
+            INTEL_INFO(dev)->gen <= 7 && !IS_HASWELL(dev)) {
+                DRM_DEBUG_KMS("disabled per chip default\n");
+                dev_priv->no_fbc_reason = FBC_CHIP_DEFAULT;
+                goto out_disable;
         }
-        if (!enable_fbc) {
+        if (!i915_enable_fbc) {
                 DRM_DEBUG_KMS("fbc disabled per module param\n");
                 dev_priv->no_fbc_reason = FBC_MODULE_PARAM;
                 goto out_disable;