drm/vc4: Free all stale dlists if channel is disabled

The code handling freeing stale dlists had 2 issues:
- it disabled the interrupt as soon as the first EOF interrupt
  occurred, even if it didn't clear all stale allocations, thus
  leading to stale entries
- It didn't free stale entries from disabled channels, so eg
  "kmstest -c 0" could leave a stale alloc on channel 1 floating
  around.

Keep the interrupt enabled whilst there are any outstanding
allocs, and discard those on disabled channels. This second
channel does require us to call vc4_hvs_stop_channel from
vc4_crtc_atomic_disable so that the channel actually gets stopped.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index ee30f2c..2a8b147 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -661,6 +661,8 @@ static void vc4_crtc_atomic_disable(struct drm_crtc *crtc,
 
        vc4_crtc_disable(crtc, encoder, state, old_vc4_state->assigned_channel);
 
+       vc4_hvs_atomic_disable(crtc, state);
+
        /*
         * Make sure we issue a vblank event after disabling the CRTC if
         * someone was waiting it.

diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
index 821bb99..e02a38d 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -697,7 +697,8 @@ static void vc4_hvs_schedule_dlist_sweep(struct vc4_hvs *hvs,
        if (!list_empty(&hvs->stale_dlist_entries))
                queue_work(system_unbound_wq, &hvs->free_dlist_work);
 
-       vc4_hvs_irq_clear_eof(hvs, channel);
+       if (list_empty(&hvs->stale_dlist_entries))
+               vc4_hvs_irq_clear_eof(hvs, channel);
 
        spin_unlock_irqrestore(&hvs->mm_lock, flags);
 }
@@ -712,6 +713,27 @@ static bool vc4_hvs_frcnt_lte(u8 cnt1, u8 cnt2)
        return (s8)((cnt1 << 2) - (cnt2 << 2)) <= 0;
 }
 
+bool vc4_hvs_check_channel_active(struct vc4_hvs *hvs, unsigned int fifo)
+{
+       struct vc4_dev *vc4 = hvs->vc4;
+       struct drm_device *drm = &vc4->base;
+       bool enabled = false;
+       int idx;
+
+       WARN_ON_ONCE(vc4->gen > VC4_GEN_6);
+
+       if (!drm_dev_enter(drm, &idx))
+               return 0;
+
+       if (vc4->gen >= VC4_GEN_6)
+               enabled = HVS_READ(SCALER6_DISPX_CTRL0(fifo)) & SCALER6_DISPX_CTRL0_ENB;
+       else
+               enabled = HVS_READ(SCALER_DISPCTRLX(fifo)) & SCALER_DISPCTRLX_ENABLE;
+
+       drm_dev_exit(idx);
+       return enabled;
+}
+
 /*
  * Some atomic commits (legacy cursor updates, mostly) will not wait for
  * the next vblank and will just return once the commit has been pushed
@@ -746,7 +768,8 @@ static void vc4_hvs_dlist_free_work(struct work_struct *work)
                u8 frcnt;
 
                frcnt = vc4_hvs_get_fifo_frame_count(hvs, cur->channel);
-               if (!vc4_hvs_frcnt_lte(cur->target_frame_count, frcnt))
+               if (vc4_hvs_check_channel_active(hvs, cur->channel) &&
+                   !vc4_hvs_frcnt_lte(cur->target_frame_count, frcnt))
                        continue;
 
                vc4_hvs_free_dlist_entry_locked(hvs, cur);