diff options
| author | Boris Brezillon <boris.brezillon@bootlin.com> | 2019-02-20 16:51:23 +0100 |
|---|---|---|
| committer | Maxime Ripard <maxime.ripard@bootlin.com> | 2019-03-06 14:48:03 +0100 |
| commit | 4686da83154d87be6e754ddc68e4ac89b0027ea9 (patch) | |
| tree | 6f2e71d7a72d1c667fc67de947ddec100cc04977 /drivers/gpu/drm/vc4/vc4_drv.h | |
| parent | 531a1b622da9adbf9f084d2ac4bf6a9f6a9acf28 (diff) | |
drm/vc4: Add a load tracker to prevent HVS underflow errors
The HVS block is supposed to fill the pixelvalve FIFOs fast enough to
meet the requested framerate. The problem is, the HVS and memory bus
bandwidths are limited, and if we don't take these limitations into
account we might end up with HVS underflow errors.
This patch is trying to model the per-plane HVS and memory bus bandwidth
consumption and take a decision at atomic_check() time whether the
estimated load will fit in the HVS and membus budget.
Note that we take an extra margin on the memory bus consumption to let
the system run smoothly when other blocks are doing heavy use of the
memory bus. Same goes for the HVS limit, except the margin is smaller in
this case, since the HVS is not used by external components.
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190220155124.25022-3-paul.kocialkowski@bootlin.com
Diffstat (limited to 'drivers/gpu/drm/vc4/vc4_drv.h')
| -rw-r--r-- | drivers/gpu/drm/vc4/vc4_drv.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h index 6f86af1b3212..bbab084911f3 100644 --- a/drivers/gpu/drm/vc4/vc4_drv.h +++ b/drivers/gpu/drm/vc4/vc4_drv.h @@ -207,6 +207,7 @@ struct vc4_dev { struct drm_modeset_lock ctm_state_lock; struct drm_private_obj ctm_manager; + struct drm_private_obj load_tracker; }; static inline struct vc4_dev * @@ -378,6 +379,16 @@ struct vc4_plane_state { * when async update is not possible. */ bool dlist_initialized; + + /* Load of this plane on the HVS block. The load is expressed in HVS + * cycles/sec. + */ + u64 hvs_load; + + /* Memory bandwidth needed for this plane. This is expressed in + * bytes/sec. + */ + u64 membus_load; }; static inline struct vc4_plane_state * |