target/linux/bcm27xx/patches-6.1/950-1163-drm-vc4-Free-the-dlist-alloc-immediately-if-it-never.patch

   1 From 51712a6493bf8824419f51ca7950e7d88f48b699 Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.com>
   3 Date: Wed, 22 Nov 2023 18:36:54 +0000
   4 Subject: [PATCH] drm: vc4: Free the dlist alloc immediately if it never hit
   5  the hw
   6
   7 atomic_check creates a state, and allocates the dlist memory for
   8 it such that atomic_flush can not fail.
   9
  10 On destroy that dlist allocation was being put in the stale list,
  11 even though it had never been programmed into the hardware,
  12 therefore doing lots of atomic_checks could consume all the dlist
  13 memory and fail.
  14
  15 If the dlist has never been programmed into the hardware, then
  16 free it immediately.
  17
  18 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
  19 ---
  20  drivers/gpu/drm/vc4/vc4_drv.h | 1 +
  21  drivers/gpu/drm/vc4/vc4_hvs.c | 6 +++++-
  22  2 files changed, 6 insertions(+), 1 deletion(-)
  23
  24 --- a/drivers/gpu/drm/vc4/vc4_drv.h
  25 +++ b/drivers/gpu/drm/vc4/vc4_drv.h
  26 @@ -696,6 +696,7 @@ struct vc4_hvs_dlist_allocation {
  27         struct drm_mm_node mm_node;
  28         unsigned int channel;
  29         u8 target_frame_count;
  30 +       bool dlist_programmed;
  31  };
  32
  33  struct vc4_crtc_state {
  34 --- a/drivers/gpu/drm/vc4/vc4_hvs.c
  35 +++ b/drivers/gpu/drm/vc4/vc4_hvs.c
  36 @@ -697,8 +697,11 @@ void vc4_hvs_mark_dlist_entry_stale(stru
  37          * Kunit tests run with a mock device and we consider any hardware
  38          * access a test failure. Let's free the dlist allocation right away if
  39          * we're running under kunit, we won't risk a dlist corruption anyway.
  40 +        *
  41 +        * Likewise if the allocation was only checked and never programmed, we
  42 +        * can destroy the allocation immediately.
  43          */
  44 -       if (kunit_get_current_test()) {
  45 +       if (kunit_get_current_test() || !alloc->dlist_programmed) {
  46                 spin_lock_irqsave(&hvs->mm_lock, flags);
  47                 vc4_hvs_free_dlist_entry_locked(hvs, alloc);
  48                 spin_unlock_irqrestore(&hvs->mm_lock, flags);
  49 @@ -1201,6 +1204,7 @@ static void vc4_hvs_install_dlist(struct
  50                 return;
  51
  52         WARN_ON(!vc4_state->mm);
  53 +       vc4_state->mm->dlist_programmed = true;
  54
  55         if (vc4->gen >= VC4_GEN_6)
  56                 HVS_WRITE(SCALER6_DISPX_LPTRS(vc4_state->assigned_channel),