target/linux/brcm2708/patches-4.4/0287-drm-vc4-Fix-spurious-GPU-resets-due-to-BO-reuse.patch

   1 From 6fde872f91f4ff8dcf1b2c2017c04e4f1dee07f7 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Mon, 8 Feb 2016 11:19:14 -0800
   4 Subject: [PATCH 287/304] drm/vc4: Fix spurious GPU resets due to BO reuse.
   5
   6 We were tracking the "where are the head pointers pointing" globally,
   7 so if another job reused the same BOs and execution was at the same
   8 point as last time we checked, we'd stop and trigger a reset even
   9 though the GPU had made progress.
  10
  11 Signed-off-by: Eric Anholt <eric@anholt.net>
  12 (cherry picked from commit c4ce60dc30912df09b2438f1e5594eae1ef64d1e)
  13 ---
  14  drivers/gpu/drm/vc4/vc4_drv.h |  6 +++++-
  15  drivers/gpu/drm/vc4/vc4_gem.c | 19 ++++++++++++++-----
  16  2 files changed, 19 insertions(+), 6 deletions(-)
  17
  18 --- a/drivers/gpu/drm/vc4/vc4_drv.h
  19 +++ b/drivers/gpu/drm/vc4/vc4_drv.h
  20 @@ -93,7 +93,6 @@ struct vc4_dev {
  21         struct work_struct overflow_mem_work;
  22
  23         struct {
  24 -               uint32_t last_ct0ca, last_ct1ca;
  25                 struct timer_list timer;
  26                 struct work_struct reset_work;
  27         } hangcheck;
  28 @@ -203,6 +202,11 @@ struct vc4_exec_info {
  29         /* Sequence number for this bin/render job. */
  30         uint64_t seqno;
  31
  32 +       /* Last current addresses the hardware was processing when the
  33 +        * hangcheck timer checked on us.
  34 +        */
  35 +       uint32_t last_ct0ca, last_ct1ca;
  36 +
  37         /* Kernel-space copy of the ioctl arguments */
  38         struct drm_vc4_submit_cl *args;
  39
  40 --- a/drivers/gpu/drm/vc4/vc4_gem.c
  41 +++ b/drivers/gpu/drm/vc4/vc4_gem.c
  42 @@ -271,10 +271,17 @@ vc4_hangcheck_elapsed(unsigned long data
  43         struct drm_device *dev = (struct drm_device *)data;
  44         struct vc4_dev *vc4 = to_vc4_dev(dev);
  45         uint32_t ct0ca, ct1ca;
  46 +       unsigned long irqflags;
  47 +       struct vc4_exec_info *exec;
  48 +
  49 +       spin_lock_irqsave(&vc4->job_lock, irqflags);
  50 +       exec = vc4_first_job(vc4);
  51
  52         /* If idle, we can stop watching for hangs. */
  53 -       if (list_empty(&vc4->job_list))
  54 +       if (!exec) {
  55 +               spin_unlock_irqrestore(&vc4->job_lock, irqflags);
  56                 return;
  57 +       }
  58
  59         ct0ca = V3D_READ(V3D_CTNCA(0));
  60         ct1ca = V3D_READ(V3D_CTNCA(1));
  61 @@ -282,14 +289,16 @@ vc4_hangcheck_elapsed(unsigned long data
  62         /* If we've made any progress in execution, rearm the timer
  63          * and wait.
  64          */
  65 -       if (ct0ca != vc4->hangcheck.last_ct0ca ||
  66 -           ct1ca != vc4->hangcheck.last_ct1ca) {
  67 -               vc4->hangcheck.last_ct0ca = ct0ca;
  68 -               vc4->hangcheck.last_ct1ca = ct1ca;
  69 +       if (ct0ca != exec->last_ct0ca || ct1ca != exec->last_ct1ca) {
  70 +               exec->last_ct0ca = ct0ca;
  71 +               exec->last_ct1ca = ct1ca;
  72 +               spin_unlock_irqrestore(&vc4->job_lock, irqflags);
  73                 vc4_queue_hangcheck(dev);
  74                 return;
  75         }
  76
  77 +       spin_unlock_irqrestore(&vc4->job_lock, irqflags);
  78 +
  79         /* We've gone too long with no progress, reset.  This has to
  80          * be done from a work struct, since resetting can sleep and
  81          * this timer hook isn't allowed to.