2 files changed, 128 insertions, 17 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e1fcd89562df..a47e5ee5dcaa 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5481,6 +5481,92 @@ static struct drm_display_mode load_detect_mode = {
                  704, 832, 0, 480, 489, 491, 520, 0, DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC),
 };
 
+static struct drm_framebuffer *
+intel_framebuffer_create(struct drm_device *dev,
+                         struct drm_mode_fb_cmd *mode_cmd,
+                         struct drm_i915_gem_object *obj)
+{
+        struct intel_framebuffer *intel_fb;
+        int ret;
+
+        intel_fb = kzalloc(sizeof(*intel_fb), GFP_KERNEL);
+        if (!intel_fb) {
+                drm_gem_object_unreference_unlocked(&obj->base);
+                return ERR_PTR(-ENOMEM);
+        }
+
+        ret = intel_framebuffer_init(dev, intel_fb, mode_cmd, obj);
+        if (ret) {
+                drm_gem_object_unreference_unlocked(&obj->base);
+                kfree(intel_fb);
+                return ERR_PTR(ret);
+        }
+
+        return &intel_fb->base;
+}
+
+static u32
+intel_framebuffer_pitch_for_width(int width, int bpp)
+{
+        u32 pitch = DIV_ROUND_UP(width * bpp, 8);
+        return ALIGN(pitch, 64);
+}
+
+static u32
+intel_framebuffer_size_for_mode(struct drm_display_mode *mode, int bpp)
+{
+        u32 pitch = intel_framebuffer_pitch_for_width(mode->hdisplay, bpp);
+        return ALIGN(pitch * mode->vdisplay, PAGE_SIZE);
+}
+
+static struct drm_framebuffer *
+intel_framebuffer_create_for_mode(struct drm_device *dev,
+                                  struct drm_display_mode *mode,
+                                  int depth, int bpp)
+{
+        struct drm_i915_gem_object *obj;
+        struct drm_mode_fb_cmd mode_cmd;
+
+        obj = i915_gem_alloc_object(dev,
+                                    intel_framebuffer_size_for_mode(mode, bpp));
+        if (obj == NULL)
+                return ERR_PTR(-ENOMEM);
+
+        mode_cmd.width = mode->hdisplay;
+        mode_cmd.height = mode->vdisplay;
+        mode_cmd.depth = depth;
+        mode_cmd.bpp = bpp;
+        mode_cmd.pitch = intel_framebuffer_pitch_for_width(mode_cmd.width, bpp);
+
+        return intel_framebuffer_create(dev, &mode_cmd, obj);
+}
+
+static struct drm_framebuffer *
+mode_fits_in_fbdev(struct drm_device *dev,
+                   struct drm_display_mode *mode)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        struct drm_i915_gem_object *obj;
+        struct drm_framebuffer *fb;
+
+        if (dev_priv->fbdev == NULL)
+                return NULL;
+
+        obj = dev_priv->fbdev->ifb.obj;
+        if (obj == NULL)
+                return NULL;
+
+        fb = &dev_priv->fbdev->ifb.base;
+        if (fb->pitch < intel_framebuffer_pitch_for_width(mode->hdisplay,
+                                                          fb->bits_per_pixel))
+                return NULL;
+
+        if (obj->base.size < mode->vdisplay * fb->pitch)
+                return NULL;
+
+        return fb;
+}
+
 bool intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
                                 struct drm_connector *connector,
                                 struct drm_display_mode *mode,
@@ -5491,8 +5577,13 @@ bool intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
         struct drm_encoder *encoder = &intel_encoder->base;
         struct drm_crtc *crtc = NULL;
         struct drm_device *dev = encoder->dev;
+        struct drm_framebuffer *old_fb;
         int i = -1;
 
+        DRM_DEBUG_KMS("[CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
+                      connector->base.id, drm_get_connector_name(connector),
+                      encoder->base.id, drm_get_encoder_name(encoder));
+
         /*
          * Algorithm gets a little messy:
          *
@@ -5551,12 +5642,38 @@ bool intel_get_load_detect_pipe(struct intel_encoder *intel_encoder,
         intel_crtc = to_intel_crtc(crtc);
         old->dpms_mode = intel_crtc->dpms_mode;
         old->load_detect_temp = true;
+        old->release_fb = NULL;
 
         if (!mode)
                 mode = &load_detect_mode;
 
-        if (!drm_crtc_helper_set_mode(crtc, mode, 0, 0, crtc->fb)) {
+        old_fb = crtc->fb;
+
+        /* We need a framebuffer large enough to accommodate all accesses
+         * that the plane may generate whilst we perform load detection.
+         * We can not rely on the fbcon either being present (we get called
+         * during its initialisation to detect all boot displays, or it may
+         * not even exist) or that it is large enough to satisfy the
+         * requested mode.
+         */
+        crtc->fb = mode_fits_in_fbdev(dev, mode);
+        if (crtc->fb == NULL) {
+                DRM_DEBUG_KMS("creating tmp fb for load-detection\n");
+                crtc->fb = intel_framebuffer_create_for_mode(dev, mode, 24, 32);
+                old->release_fb = crtc->fb;
+        } else
+                DRM_DEBUG_KMS("reusing fbdev for load-detection framebuffer\n");
+        if (IS_ERR(crtc->fb)) {
+                DRM_DEBUG_KMS("failed to allocate framebuffer for load-detection\n");
+                crtc->fb = old_fb;
+                return false;
+        }
+
+        if (!drm_crtc_helper_set_mode(crtc, mode, 0, 0, old_fb)) {
                 DRM_DEBUG_KMS("failed to set mode on load-detect pipe\n");
+                if (old->release_fb)
+                        old->release_fb->funcs->destroy(old->release_fb);
+                crtc->fb = old_fb;
                 return false;
         }
 
@@ -5576,9 +5693,17 @@ void intel_release_load_detect_pipe(struct intel_encoder *intel_encoder,
         struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
         struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 
+        DRM_DEBUG_KMS("[CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
+                      connector->base.id, drm_get_connector_name(connector),
+                      encoder->base.id, drm_get_encoder_name(encoder));
+
         if (old->load_detect_temp) {
                 connector->encoder = NULL;
                 drm_helper_disable_unused_functions(dev);
+
+                if (old->release_fb)
+                        old->release_fb->funcs->destroy(old->release_fb);
+
                 return;
         }
 
@@ -6566,27 +6691,12 @@ intel_user_framebuffer_create(struct drm_device *dev,
                               struct drm_mode_fb_cmd *mode_cmd)
 {
         struct drm_i915_gem_object *obj;
-        struct intel_framebuffer *intel_fb;
-        int ret;
 
         obj = to_intel_bo(drm_gem_object_lookup(dev, filp, mode_cmd->handle));
         if (&obj->base == NULL)
                 return ERR_PTR(-ENOENT);
 
-        intel_fb = kzalloc(sizeof(*intel_fb), GFP_KERNEL);
-        if (!intel_fb) {
-                drm_gem_object_unreference_unlocked(&obj->base);
-                return ERR_PTR(-ENOMEM);
-        }
-
-        ret = intel_framebuffer_init(dev, intel_fb, mode_cmd, obj);
-        if (ret) {
-                drm_gem_object_unreference_unlocked(&obj->base);
-                kfree(intel_fb);
-                return ERR_PTR(ret);
-        }
-
-        return &intel_fb->base;
+        return intel_framebuffer_create(dev, mode_cmd, obj);
 }
 
 static const struct drm_mode_config_funcs intel_mode_funcs = {
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 3ceb3daeb61f..2e49b62da9a5 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -292,6 +292,7 @@ extern void intel_wait_for_vblank(struct drm_device *dev, int pipe);
 extern void intel_wait_for_pipe_off(struct drm_device *dev, int pipe);
 
 struct intel_load_detect_pipe {
+        struct drm_framebuffer *release_fb;
         bool load_detect_temp;
         int dpms_mode;
 };