target/linux/bcm27xx/patches-5.4/950-0227-drm-v3d-Skip-MMU-flush-if-the-device-is-currently-of.patch

   1 From f34daf3b5ae9533f88d31eef74bbf38099e96aa1 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Mon, 14 Jan 2019 12:35:43 -0800
   4 Subject: [PATCH] drm/v3d: Skip MMU flush if the device is currently
   5  off.
   6
   7 If it's off, we know it will be reset on poweron, so the MMU won't
   8 have any TLB cached from before this point.  Avoids failed waits for
   9 MMU flush to reply.
  10
  11 Signed-off-by: Eric Anholt <eric@anholt.net>
  12 (cherry picked from commit 3ee4e2e0a9e9587eacbb69b067bbc72ab2cdc47b)
  13 ---
  14  drivers/gpu/drm/v3d/v3d_mmu.c | 13 +++++++++++++
  15  1 file changed, 13 insertions(+)
  16
  17 --- a/drivers/gpu/drm/v3d/v3d_mmu.c
  18 +++ b/drivers/gpu/drm/v3d/v3d_mmu.c
  19 @@ -18,6 +18,8 @@
  20   * each client.  This is not yet implemented.
  21   */
  22
  23 +#include <linux/pm_runtime.h>
  24 +
  25  #include "v3d_drv.h"
  26  #include "v3d_regs.h"
  27
  28 @@ -34,6 +36,14 @@ static int v3d_mmu_flush_all(struct v3d_
  29  {
  30         int ret;
  31
  32 +       /* Keep power on the device on until we're done with this
  33 +        * call, but skip the flush if the device is off and will be
  34 +        * reset when powered back on.
  35 +        */
  36 +       ret = pm_runtime_get_if_in_use(v3d->dev);
  37 +       if (ret == 0)
  38 +               return 0;
  39 +
  40         /* Make sure that another flush isn't already running when we
  41          * start this one.
  42          */
  43 @@ -61,6 +71,9 @@ static int v3d_mmu_flush_all(struct v3d_
  44         if (ret)
  45                 dev_err(v3d->dev, "MMUC flush wait idle failed\n");
  46
  47 +       pm_runtime_mark_last_busy(v3d->dev);
  48 +       pm_runtime_put_autosuspend(v3d->dev);
  49 +
  50         return ret;
  51  }
  52