From 2e2b65c1c67b7a918fc381c25f8d5e3f2be2295c Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.org>
Date: Wed, 13 Feb 2019 12:36:56 +0000
Subject: [PATCH] staging: mmal-vchiq: Always return the param size
 from param_get

mmal-vchiq is a reimplementation of the userland library for MMAL.
When getting a parameter, the client provides the storage and
the size of the storage. The VPU then returns the size of the
parameter that it wished to return, and as much as possible of
that parameter is returned to the client.

The implementation previously only returned the size provided
by the VPU should it exceed the buffer size. So for parameters
such as the supported encodings list the client had no idea
how much of the provided storage had been populated.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
---
 drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
+++ b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c
@@ -1412,11 +1412,12 @@ static int port_parameter_get(struct vch
 		 */
 		memcpy(value, &rmsg->u.port_parameter_get_reply.value,
 		       *value_size);
-		*value_size = rmsg->u.port_parameter_get_reply.size;
 	} else {
 		memcpy(value, &rmsg->u.port_parameter_get_reply.value,
 		       rmsg->u.port_parameter_get_reply.size);
 	}
+	/* Always report the size of the returned parameter to the caller */
+	*value_size = rmsg->u.port_parameter_get_reply.size;
 
 	pr_debug("%s:result:%d component:0x%x port:%d parameter:%d\n", __func__,
 		 ret, port->component->handle, port->handle, parameter_id);
