drm/udl: make usage as a console safer

Okay you don't really want to use udl devices as your console, but if
you are unlucky enough to do so, you run into a lot of schedule while atomic
due to printk being called from all sorts of funky places. So check if we
are in an atomic context, and queue the damage for later, the next printk
should cause it to appear. This isn't ideal, but it is simple, and seems to
work okay in my testing here.

(dirty area idea came from xenfb)

fixes a bunch of sleeping while atomic issues running fbcon on udl devices.

Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
index 87aa5f5..cc6d90f 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -75,6 +75,8 @@ struct udl_framebuffer {
 	struct drm_framebuffer base;
 	struct udl_gem_object *obj;
 	bool active_16; /* active on the 16-bit channel */
+	int x1, y1, x2, y2; /* dirty rect */
+	spinlock_t dirty_lock;
 };
 
 #define to_udl_fb(x) container_of(x, struct udl_framebuffer, base)