[PATCH v7 18/19] media: meson: vdec: Increase VIFIFO buffer size to 32 MiB

[Anand Moon <linux.amoon@gmail.com>]

During 4K video playback, the hardware Elementary Stream Parser (esparser)
can rapidly push massive burst data payloads into the Video Input FIFO
faster than the VPU decoding block can consume it. This causes a buffer
overflow when stream usage breaks past the allocated hardware boundary:

[ 1852.587956] meson-vdec ff620000.video-decoder: VIFIFO usage (16779003) > VIFIFO size (16777216)

When this overflow happens on Amlogic SoCs, it triggers an invalid memory
state, leading to stream corruption and fatal kernel panic lockups within
videobuf2 error rollback handling routines.

Double the parsed bitstream swap exchange memory pool (SIZE_VIFIFO) from
16 MiB (SZ_16M) to 32 MiB (SZ_32M). This provides a larger canvas window
to cushion high-frequency frame reordering spikes and prevents the VPU
from crashing on demanding modern streams.

Cc: Nicolas Dufresne <nicolas@ndufresne.ca>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
---
 drivers/staging/media/meson/vdec/vdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/media/meson/vdec/vdec.c b/drivers/staging/media/meson/vdec/vdec.c
index d33cbebc4453b..824e2f156adeb 100644
--- a/drivers/staging/media/meson/vdec/vdec.c
+++ b/drivers/staging/media/meson/vdec/vdec.c
@@ -29,8 +29,8 @@ struct dummy_buf {
 	struct list_head list;
 };
 
-/* 16 MiB for parsed bitstream swap exchange */
-#define SIZE_VIFIFO SZ_16M
+/* 32 MiB for parsed bitstream swap exchange */
+#define SIZE_VIFIFO SZ_32M
 
 static void vdec_free_canvas(struct amvdec_session *sess);
 static void vdec_reset_timestamps(struct amvdec_session *sess);
-- 
2.50.1