On Fri Jan 9 11:15:29 2026 -0500, Detlev Casanova wrote:
> Similarly to what is done in Hantro, avoid exposing equal video codecs to
> userspace. Equal video codecs allow scheduling work between the cores.
> For that kernel support is required, which does not yet exist.
> Until that is implemented, avoid exposing each core separately to
> userspace so that multicore can be added in the future without breaking
> userspace ABI.
>
> This currently applies only to RK3588 which has 2 equal VDPU381 decoders,
> but will be applied for all SoC supported by rkvdec that has multiple DTS
> nodes with the same compatible.
>
> Reviewed-by: Nicolas Dufresne <[email protected]>
> Signed-off-by: Detlev Casanova <[email protected]>
> Signed-off-by: Nicolas Dufresne <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Patch committed.
Thanks,
Hans Verkuil
drivers/media/platform/rockchip/rkvdec/rkvdec.c | 47 +++++++++++++++++++++++++
1 file changed, 47 insertions(+)
---
diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec.c
b/drivers/media/platform/rockchip/rkvdec/rkvdec.c
index ce96a0470d4d..af2eced90026 100644
--- a/drivers/media/platform/rockchip/rkvdec/rkvdec.c
+++ b/drivers/media/platform/rockchip/rkvdec/rkvdec.c
@@ -1269,6 +1269,49 @@ static void rkvdec_watchdog_func(struct work_struct
*work)
}
}
+/*
+ * Some SoCs, like RK3588 have multiple identical VDPU cores, but the
+ * kernel is currently missing support for multi-core handling. Exposing
+ * separate devices for each core to userspace is bad, since that does
+ * not allow scheduling tasks properly (and creates ABI). With this workaround
+ * the driver will only probe for the first core and early exit for the other
+ * cores. Once the driver gains multi-core support, the same technique
+ * for detecting the first core can be used to cluster all cores together.
+ */
+static int rkvdec_disable_multicore(struct rkvdec_dev *rkvdec)
+{
+ struct device_node *node = NULL;
+ const char *compatible;
+ bool is_first_core;
+ int ret;
+
+ /* Intentionally ignores the fallback strings */
+ ret = of_property_read_string(rkvdec->dev->of_node, "compatible",
&compatible);
+ if (ret)
+ return ret;
+
+ /* The first compatible and available node found is considered the main
core */
+ do {
+ node = of_find_compatible_node(node, NULL, compatible);
+ if (of_device_is_available(node))
+ break;
+ } while (node);
+
+ if (!node)
+ return -EINVAL;
+
+ is_first_core = (rkvdec->dev->of_node == node);
+
+ of_node_put(node);
+
+ if (!is_first_core) {
+ dev_info(rkvdec->dev, "missing multi-core support, ignoring
this instance\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
static const struct rkvdec_variant_ops rk3399_variant_ops = {
.irq_handler = rk3399_irq_handler,
};
@@ -1332,6 +1375,10 @@ static int rkvdec_probe(struct platform_device *pdev)
mutex_init(&rkvdec->vdev_lock);
INIT_DELAYED_WORK(&rkvdec->watchdog_work, rkvdec_watchdog_func);
+ ret = rkvdec_disable_multicore(rkvdec);
+ if (ret)
+ return ret;
+
ret = devm_clk_bulk_get_all_enabled(&pdev->dev, &rkvdec->clocks);
if (ret < 0)
return ret;
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