[PATCH v4 6/7] drm/log: Implement suspend/resume

[Jocelyn Falempe <jfalempe@redhat.com>]

The console is already suspended in printk.c.
Just make sure we don't write to the framebuffer while the graphic
driver is suspended.
It may lose a few messages between graphic suspend and console
suspend.

Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
---
 drivers/gpu/drm/drm_log.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/drm_log.c b/drivers/gpu/drm/drm_log.c
index 635dff7b37ce..07d151300146 100644
--- a/drivers/gpu/drm/drm_log.c
+++ b/drivers/gpu/drm/drm_log.c
@@ -50,6 +50,7 @@ struct drm_log {
 	struct drm_client_dev client;
 	struct console con;
 	bool probed;
+	bool suspended;
 	u32 n_scanout;
 	struct drm_log_scanout *scanout;
 };
@@ -310,10 +311,32 @@ static int drm_log_client_hotplug(struct drm_client_dev *client)
 	return 0;
 }
 
+static int drm_log_client_suspend(struct drm_client_dev *client, bool _console_lock)
+{
+	struct drm_log *dlog = client_to_drm_log(client);
+
+	mutex_lock(&dlog->lock);
+	dlog->suspended = true;
+	mutex_unlock(&dlog->lock);
+	return 0;
+}
+
+static int drm_log_client_resume(struct drm_client_dev *client, bool _console_lock)
+{
+	struct drm_log *dlog = client_to_drm_log(client);
+
+	mutex_lock(&dlog->lock);
+	dlog->suspended = false;
+	mutex_unlock(&dlog->lock);
+	return 0;
+}
+
 static const struct drm_client_funcs drm_log_client_funcs = {
 	.owner		= THIS_MODULE,
 	.unregister	= drm_log_client_unregister,
 	.hotplug	= drm_log_client_hotplug,
+	.suspend	= drm_log_client_suspend,
+	.resume		= drm_log_client_resume,
 };
 
 static void drm_log_write_thread(struct console *con, struct nbcon_write_context *wctxt)
@@ -321,6 +344,9 @@ static void drm_log_write_thread(struct console *con, struct nbcon_write_context
 	struct drm_log *dlog = console_to_drm_log(con);
 	int i;
 
+	if (dlog->suspended)
+		return;
+
 	if (!dlog->probed)
 		drm_log_init_client(dlog);
 
-- 
2.46.2