drm/nouveau/fbcon: take runpm reference when userspace has an open fd

We need to do this in order to prevent accesses to the device while it's
powered down.  Userspace may have an mmap of the fb, and there's no good
way (that I know of) to prevent it from touching the device otherwise.

This fixes some nasty races between runpm and plymouth on some systems,
which result in the GPU getting very upset and hanging the boot.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
index 2791701685dc82bf4e2655ce3ea8ea6c3b278e49..59f27e774acb5e9c98c9854bd72195efdbec3a48 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -178,8 +178,30 @@ nouveau_fbcon_sync(struct fb_info *info)
        return 0;
 }
 
+static int
+nouveau_fbcon_open(struct fb_info *info, int user)
+{
+       struct nouveau_fbdev *fbcon = info->par;
+       struct nouveau_drm *drm = nouveau_drm(fbcon->dev);
+       int ret = pm_runtime_get_sync(drm->dev->dev);
+       if (ret < 0 && ret != -EACCES)
+               return ret;
+       return 0;
+}
+
+static int
+nouveau_fbcon_release(struct fb_info *info, int user)
+{
+       struct nouveau_fbdev *fbcon = info->par;
+       struct nouveau_drm *drm = nouveau_drm(fbcon->dev);
+       pm_runtime_put(drm->dev->dev);
+       return 0;
+}
+
 static struct fb_ops nouveau_fbcon_ops = {
        .owner = THIS_MODULE,
+       .fb_open = nouveau_fbcon_open,
+       .fb_release = nouveau_fbcon_release,
        .fb_check_var = drm_fb_helper_check_var,
        .fb_set_par = drm_fb_helper_set_par,
        .fb_fillrect = nouveau_fbcon_fillrect,
@@ -195,6 +217,8 @@ static struct fb_ops nouveau_fbcon_ops = {
 
 static struct fb_ops nouveau_fbcon_sw_ops = {
        .owner = THIS_MODULE,
+       .fb_open = nouveau_fbcon_open,
+       .fb_release = nouveau_fbcon_release,
        .fb_check_var = drm_fb_helper_check_var,
        .fb_set_par = drm_fb_helper_set_par,
        .fb_fillrect = drm_fb_helper_cfb_fillrect,