drm/i915: restore only the mode of this driver on lastclose (v2)

i915 calls the panic handler function on last close to reset the modes,
however this is a really bad idea for multi-gpu machines, esp shareable
gpus machines. So add a new entry point for the driver to just restore
its own fbcon mode.

v2: move code into fb helper, fix panic code to block mode change on
powered off GPUs.

[airlied: this hits drm core and I wrote it and it was reviewed on intel-gfx
 so really I signed it off twice ;-).]
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

5 files changed, 33 insertions, 8 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 950720473967..11d7a72c22d9 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -342,9 +342,22 @@ int drm_fb_helper_debug_leave(struct fb_info *info)
 }
 EXPORT_SYMBOL(drm_fb_helper_debug_leave);
 
+bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
+{
+        bool error = false;
+        int i, ret;
+        for (i = 0; i < fb_helper->crtc_count; i++) {
+                struct drm_mode_set *mode_set = &fb_helper->crtc_info[i].mode_set;
+                ret = drm_crtc_helper_set_config(mode_set);
+                if (ret)
+                        error = true;
+        }
+        return error;
+}
+EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode);
+
 bool drm_fb_helper_force_kernel_mode(void)
 {
-        int i = 0;
         bool ret, error = false;
         struct drm_fb_helper *helper;
 
@@ -352,12 +365,12 @@ bool drm_fb_helper_force_kernel_mode(void)
                 return false;
 
         list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
-                for (i = 0; i < helper->crtc_count; i++) {
-                        struct drm_mode_set *mode_set = &helper->crtc_info[i].mode_set;
-                        ret = drm_crtc_helper_set_config(mode_set);
-                        if (ret)
-                                error = true;
-                }
+                if (helper->dev->switch_power_state == DRM_SWITCH_POWER_OFF)
+                        continue;
+
+                ret = drm_fb_helper_restore_fbdev_mode(helper);
+                if (ret)
+                        error = true;
         }
         return error;
 }
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 72730377a01b..12876f2795d2 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -2207,7 +2207,7 @@ void i915_driver_lastclose(struct drm_device * dev)
         drm_i915_private_t *dev_priv = dev->dev_private;
 
         if (!dev_priv || drm_core_check_feature(dev, DRIVER_MODESET)) {
-                drm_fb_helper_restore();
+                intel_fb_restore_mode(dev);
                 vga_switcheroo_process_delayed_switch();
                 return;
         }
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index f5b0d8306d83..1d20712d527f 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -338,4 +338,5 @@ extern int intel_overlay_attrs(struct drm_device *dev, void *data,
                                struct drm_file *file_priv);
 
 extern void intel_fb_output_poll_changed(struct drm_device *dev);
+extern void intel_fb_restore_mode(struct drm_device *dev);
 #endif /* __INTEL_DRV_H__ */
diff --git a/drivers/gpu/drm/i915/intel_fb.c b/drivers/gpu/drm/i915/intel_fb.c
index 512782728e51..ec49bae73382 100644
--- a/drivers/gpu/drm/i915/intel_fb.c
+++ b/drivers/gpu/drm/i915/intel_fb.c
@@ -264,3 +264,13 @@ void intel_fb_output_poll_changed(struct drm_device *dev)
         drm_i915_private_t *dev_priv = dev->dev_private;
         drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
 }
+
+void intel_fb_restore_mode(struct drm_device *dev)
+{
+        int ret;
+        drm_i915_private_t *dev_priv = dev->dev_private;
+
+        ret = drm_fb_helper_restore_fbdev_mode(&dev_priv->fbdev->helper);
+        if (ret)
+                DRM_DEBUG("failed to restore crtc mode\n");
+}
diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
index f22e7fe4b6db..ade09d7b4271 100644
--- a/include/drm/drm_fb_helper.h
+++ b/include/drm/drm_fb_helper.h
@@ -118,6 +118,7 @@ int drm_fb_helper_setcolreg(unsigned regno,
                             unsigned transp,
                             struct fb_info *info);
 
+bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper);
 void drm_fb_helper_restore(void);
 void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helper,
                             uint32_t fb_width, uint32_t fb_height);