drm/v3d: Skip MMU flush if the device is currently off.

If it's off, we know it will be reset on poweron, so the MMU won't
have any TLB cached from before this point.  Avoids failed waits for
MMU flush to reply.

Signed-off-by: Eric Anholt <eric@anholt.net>
(cherry picked from commit 3ee4e2e0a9e9587eacbb69b067bbc72ab2cdc47b)

diff --git a/drivers/gpu/drm/v3d/v3d_mmu.c b/drivers/gpu/drm/v3d/v3d_mmu.c
index 395e81d..6cc67ca 100644 (file)
--- a/drivers/gpu/drm/v3d/v3d_mmu.c
+++ b/drivers/gpu/drm/v3d/v3d_mmu.c
@@ -18,6 +18,8 @@
  * each client.  This is not yet implemented.
  */
 
+#include <linux/pm_runtime.h>
+
 #include "v3d_drv.h"
 #include "v3d_regs.h"
 
@@ -34,6 +36,14 @@ static int v3d_mmu_flush_all(struct v3d_dev *v3d)
 {
        int ret;
 
+       /* Keep power on the device on until we're done with this
+        * call, but skip the flush if the device is off and will be
+        * reset when powered back on.
+        */
+       ret = pm_runtime_get_if_in_use(v3d->dev);
+       if (ret == 0)
+               return 0;
+
        /* Make sure that another flush isn't already running when we
         * start this one.
         */
@@ -61,6 +71,9 @@ static int v3d_mmu_flush_all(struct v3d_dev *v3d)
        if (ret)
                dev_err(v3d->dev, "MMUC flush wait idle failed\n");
 
+       pm_runtime_mark_last_busy(v3d->dev);
+       pm_runtime_put_autosuspend(v3d->dev);
+
        return ret;
 }