4 files changed, 116 insertions, 84 deletions

diff --git a/drivers/staging/media/ipu3/Kconfig b/drivers/staging/media/ipu3/Kconfig
index f80f3e35f431..4b51c67eac88 100644
--- a/drivers/staging/media/ipu3/Kconfig
+++ b/drivers/staging/media/ipu3/Kconfig
@@ -6,7 +6,7 @@ config VIDEO_IPU3_IMGU
 	depends on X86
 	select IOMMU_IOVA
 	select VIDEOBUF2_DMA_SG
-	---help---
+	help
 	  This is the Video4Linux2 driver for Intel IPU3 image processing unit,
 	  found in Intel Skylake and Kaby Lake SoCs and used for processing
 	  images and video.
diff --git a/drivers/staging/media/ipu3/ipu3-css.c b/drivers/staging/media/ipu3/ipu3-css.c
index 15ab77e4b766..23cf5b2cfe8b 100644
--- a/drivers/staging/media/ipu3/ipu3-css.c
+++ b/drivers/staging/media/ipu3/ipu3-css.c
@@ -3,6 +3,7 @@
 
 #include <linux/device.h>
 #include <linux/iopoll.h>
+#include <linux/slab.h>
 
 #include "ipu3-css.h"
 #include "ipu3-css-fw.h"
@@ -1744,15 +1745,18 @@ int imgu_css_fmt_try(struct imgu_css *css,
 	struct v4l2_rect *const bds = &r[IPU3_CSS_RECT_BDS];
 	struct v4l2_rect *const env = &r[IPU3_CSS_RECT_ENVELOPE];
 	struct v4l2_rect *const gdc = &r[IPU3_CSS_RECT_GDC];
-	struct imgu_css_queue q[IPU3_CSS_QUEUES];
-	struct v4l2_pix_format_mplane *const in =
-					&q[IPU3_CSS_QUEUE_IN].fmt.mpix;
-	struct v4l2_pix_format_mplane *const out =
-					&q[IPU3_CSS_QUEUE_OUT].fmt.mpix;
-	struct v4l2_pix_format_mplane *const vf =
-					&q[IPU3_CSS_QUEUE_VF].fmt.mpix;
+	struct imgu_css_queue *q;
+	struct v4l2_pix_format_mplane *in, *out, *vf;
 	int i, s, ret;
 
+	q = kcalloc(IPU3_CSS_QUEUES, sizeof(struct imgu_css_queue), GFP_KERNEL);
+	if (!q)
+		return -ENOMEM;
+
+	in  = &q[IPU3_CSS_QUEUE_IN].fmt.mpix;
+	out = &q[IPU3_CSS_QUEUE_OUT].fmt.mpix;
+	vf  = &q[IPU3_CSS_QUEUE_VF].fmt.mpix;
+
 	/* Adjust all formats, get statistics buffer sizes and formats */
 	for (i = 0; i < IPU3_CSS_QUEUES; i++) {
 		if (fmts[i])
@@ -1766,7 +1770,8 @@ int imgu_css_fmt_try(struct imgu_css *css,
 					IPU3_CSS_QUEUE_TO_FLAGS(i))) {
 			dev_notice(css->dev, "can not initialize queue %s\n",
 				   qnames[i]);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto out;
 		}
 	}
 	for (i = 0; i < IPU3_CSS_RECTS; i++) {
@@ -1788,7 +1793,8 @@ int imgu_css_fmt_try(struct imgu_css *css,
 	if (!imgu_css_queue_enabled(&q[IPU3_CSS_QUEUE_IN]) ||
 	    !imgu_css_queue_enabled(&q[IPU3_CSS_QUEUE_OUT])) {
 		dev_warn(css->dev, "required queues are disabled\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out;
 	}
 
 	if (!imgu_css_queue_enabled(&q[IPU3_CSS_QUEUE_OUT])) {
@@ -1829,7 +1835,8 @@ int imgu_css_fmt_try(struct imgu_css *css,
 	ret = imgu_css_find_binary(css, pipe, q, r);
 	if (ret < 0) {
 		dev_err(css->dev, "failed to find suitable binary\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto out;
 	}
 	css->pipes[pipe].bindex = ret;
 
@@ -1843,7 +1850,8 @@ int imgu_css_fmt_try(struct imgu_css *css,
 						IPU3_CSS_QUEUE_TO_FLAGS(i))) {
 				dev_err(css->dev,
 					"final resolution adjustment failed\n");
-				return -EINVAL;
+				ret = -EINVAL;
+				goto out;
 			}
 			*fmts[i] = q[i].fmt.mpix;
 		}
@@ -1859,7 +1867,10 @@ int imgu_css_fmt_try(struct imgu_css *css,
 		 bds->width, bds->height, gdc->width, gdc->height,
 		 out->width, out->height, vf->width, vf->height);
 
-	return 0;
+	ret = 0;
+out:
+	kfree(q);
+	return ret;
 }
 
 int imgu_css_fmt_set(struct imgu_css *css,
@@ -2160,11 +2171,6 @@ int imgu_css_set_parameters(struct imgu_css *css, unsigned int pipe,
 	obgrid_size = imgu_css_fw_obgrid_size(bi);
 	stripes = bi->info.isp.sp.iterator.num_stripes ? : 1;
 
-	/*
-	 * TODO(b/118782861): If userspace queues more than 4 buffers, the
-	 * parameters from previous buffers will be overwritten. Fix the driver
-	 * not to allow this.
-	 */
 	imgu_css_pool_get(&css_pipe->pool.parameter_set_info);
 	param_set = imgu_css_pool_last(&css_pipe->pool.parameter_set_info,
 				       0)->vaddr;
diff --git a/drivers/staging/media/ipu3/ipu3-v4l2.c b/drivers/staging/media/ipu3/ipu3-v4l2.c
index 9c0352b193a7..a7bc22040ed8 100644
--- a/drivers/staging/media/ipu3/ipu3-v4l2.c
+++ b/drivers/staging/media/ipu3/ipu3-v4l2.c
@@ -66,7 +66,7 @@ static int imgu_subdev_s_stream(struct v4l2_subdev *sd, int enable)
 	struct imgu_css_pipe *css_pipe = &imgu->css.pipes[pipe];
 	struct imgu_media_pipe *imgu_pipe = &imgu->imgu_pipe[pipe];
 
-	dev_dbg(dev, "%s %d for pipe %d", __func__, enable, pipe);
+	dev_dbg(dev, "%s %d for pipe %u", __func__, enable, pipe);
 	/* grab ctrl after streamon and return after off */
 	v4l2_ctrl_grab(imgu_sd->ctrl, enable);
 
@@ -101,7 +101,7 @@ static int imgu_subdev_s_stream(struct v4l2_subdev *sd, int enable)
 	else
 		css_pipe->pipe_id = IPU3_CSS_PIPE_ID_CAPTURE;
 
-	dev_dbg(dev, "IPU3 pipe %d pipe_id %d", pipe, css_pipe->pipe_id);
+	dev_dbg(dev, "IPU3 pipe %u pipe_id %u", pipe, css_pipe->pipe_id);
 
 	rects[IPU3_CSS_RECT_EFFECTIVE] = &imgu_sd->rect.eff;
 	rects[IPU3_CSS_RECT_BDS] = &imgu_sd->rect.bds;
@@ -109,7 +109,7 @@ static int imgu_subdev_s_stream(struct v4l2_subdev *sd, int enable)
 
 	r = imgu_css_fmt_set(&imgu->css, fmts, rects, pipe);
 	if (r) {
-		dev_err(dev, "failed to set initial formats pipe %d with (%d)",
+		dev_err(dev, "failed to set initial formats pipe %u with (%d)",
 			pipe, r);
 		return r;
 	}
@@ -157,7 +157,7 @@ static int imgu_subdev_set_fmt(struct v4l2_subdev *sd,
 	u32 pad = fmt->pad;
 	unsigned int pipe = imgu_sd->pipe;
 
-	dev_dbg(&imgu->pci_dev->dev, "set subdev %d pad %d fmt to [%dx%d]",
+	dev_dbg(&imgu->pci_dev->dev, "set subdev %u pad %u fmt to [%ux%u]",
 		pipe, pad, fmt->format.width, fmt->format.height);
 
 	imgu_pipe = &imgu->imgu_pipe[pipe];
@@ -233,7 +233,7 @@ static int imgu_subdev_set_selection(struct v4l2_subdev *sd,
 	struct v4l2_rect *rect, *try_sel;
 
 	dev_dbg(&imgu->pci_dev->dev,
-		 "set subdev %d sel which %d target 0x%4x rect [%dx%d]",
+		 "set subdev %u sel which %u target 0x%4x rect [%ux%u]",
 		 imgu_sd->pipe, sel->which, sel->target,
 		 sel->r.width, sel->r.height);
 
@@ -279,7 +279,7 @@ static int imgu_link_setup(struct media_entity *entity,
 
 	WARN_ON(pad >= IMGU_NODE_NUM);
 
-	dev_dbg(&imgu->pci_dev->dev, "pipe %d pad %d is %s", pipe, pad,
+	dev_dbg(&imgu->pci_dev->dev, "pipe %u pad %u is %s", pipe, pad,
 		 flags & MEDIA_LNK_FL_ENABLED ? "enabled" : "disabled");
 
 	imgu_pipe = &imgu->imgu_pipe[pipe];
@@ -294,7 +294,7 @@ static int imgu_link_setup(struct media_entity *entity,
 	else
 		__clear_bit(pipe, imgu->css.enabled_pipes);
 
-	dev_dbg(&imgu->pci_dev->dev, "pipe %d is %s", pipe,
+	dev_dbg(&imgu->pci_dev->dev, "pipe %u is %s", pipe,
 		 flags & MEDIA_LNK_FL_ENABLED ? "enabled" : "disabled");
 
 	return 0;
@@ -341,8 +341,10 @@ static void imgu_vb2_buf_queue(struct vb2_buffer *vb)
 	struct imgu_video_device *node =
 		container_of(vb->vb2_queue, struct imgu_video_device, vbq);
 	unsigned int queue = imgu_node_to_queue(node->id);
+	struct imgu_buffer *buf = container_of(vb, struct imgu_buffer,
+					       vid_buf.vbb.vb2_buf);
 	unsigned long need_bytes;
-	unsigned int pipe = node->pipe;
+	unsigned long payload = vb2_get_plane_payload(vb, 0);
 
 	if (vb->vb2_queue->type == V4L2_BUF_TYPE_META_CAPTURE ||
 	    vb->vb2_queue->type == V4L2_BUF_TYPE_META_OUTPUT)
@@ -350,42 +352,26 @@ static void imgu_vb2_buf_queue(struct vb2_buffer *vb)
 	else
 		need_bytes = node->vdev_fmt.fmt.pix_mp.plane_fmt[0].sizeimage;
 
-	if (queue == IPU3_CSS_QUEUE_PARAMS) {
-		unsigned long payload = vb2_get_plane_payload(vb, 0);
-		struct vb2_v4l2_buffer *buf =
-			container_of(vb, struct vb2_v4l2_buffer, vb2_buf);
-		int r = -EINVAL;
-
-		if (payload == 0) {
-			payload = need_bytes;
-			vb2_set_plane_payload(vb, 0, payload);
-		}
-		if (payload >= need_bytes)
-			r = imgu_css_set_parameters(&imgu->css, pipe,
-						    vb2_plane_vaddr(vb, 0));
-		buf->flags = V4L2_BUF_FLAG_DONE;
-		vb2_buffer_done(vb, r == 0 ? VB2_BUF_STATE_DONE
-					   : VB2_BUF_STATE_ERROR);
-
-	} else {
-		struct imgu_buffer *buf = container_of(vb, struct imgu_buffer,
-						       vid_buf.vbb.vb2_buf);
+	if (queue == IPU3_CSS_QUEUE_PARAMS && payload && payload < need_bytes) {
+		dev_err(&imgu->pci_dev->dev, "invalid data size for params.");
+		vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
+		return;
+	}
 
-		mutex_lock(&imgu->lock);
+	mutex_lock(&imgu->lock);
+	if (queue != IPU3_CSS_QUEUE_PARAMS)
 		imgu_css_buf_init(&buf->css_buf, queue, buf->map.daddr);
-		list_add_tail(&buf->vid_buf.list,
-			      &node->buffers);
-		mutex_unlock(&imgu->lock);
 
-		vb2_set_plane_payload(&buf->vid_buf.vbb.vb2_buf, 0, need_bytes);
+	list_add_tail(&buf->vid_buf.list, &node->buffers);
+	mutex_unlock(&imgu->lock);
 
-		if (imgu->streaming)
-			imgu_queue_buffers(imgu, false, pipe);
-	}
+	vb2_set_plane_payload(vb, 0, need_bytes);
 
-	dev_dbg(&imgu->pci_dev->dev, "%s for pipe %d node %d", __func__,
-		node->pipe, node->id);
+	if (imgu->streaming)
+		imgu_queue_buffers(imgu, false, node->pipe);
 
+	dev_dbg(&imgu->pci_dev->dev, "%s for pipe %u node %u", __func__,
+		node->pipe, node->id);
 }
 
 static int imgu_vb2_queue_setup(struct vb2_queue *vq,
@@ -435,7 +421,7 @@ static bool imgu_all_nodes_streaming(struct imgu_device *imgu,
 	pipe = except->pipe;
 	if (!test_bit(pipe, imgu->css.enabled_pipes)) {
 		dev_warn(&imgu->pci_dev->dev,
-			 "pipe %d link is not ready yet", pipe);
+			 "pipe %u link is not ready yet", pipe);
 		return false;
 	}
 
@@ -479,7 +465,7 @@ static int imgu_vb2_start_streaming(struct vb2_queue *vq, unsigned int count)
 	int r;
 	unsigned int pipe;
 
-	dev_dbg(dev, "%s node name %s pipe %d id %u", __func__,
+	dev_dbg(dev, "%s node name %s pipe %u id %u", __func__,
 		node->name, node->pipe, node->id);
 
 	if (imgu->streaming) {
@@ -539,7 +525,7 @@ static void imgu_vb2_stop_streaming(struct vb2_queue *vq)
 	WARN_ON(!node->enabled);
 
 	pipe = node->pipe;
-	dev_dbg(dev, "Try to stream off node [%d][%d]", pipe, node->id);
+	dev_dbg(dev, "Try to stream off node [%u][%u]", pipe, node->id);
 	imgu_pipe = &imgu->imgu_pipe[pipe];
 	r = v4l2_subdev_call(&imgu_pipe->imgu_sd.subdev, video, s_stream, 0);
 	if (r)
@@ -664,20 +650,19 @@ static int imgu_fmt(struct imgu_device *imgu, unsigned int pipe, int node,
 		    struct v4l2_format *f, bool try)
 {
 	struct device *dev = &imgu->pci_dev->dev;
-	struct v4l2_pix_format_mplane try_fmts[IPU3_CSS_QUEUES];
 	struct v4l2_pix_format_mplane *fmts[IPU3_CSS_QUEUES] = { NULL };
 	struct v4l2_rect *rects[IPU3_CSS_RECTS] = { NULL };
 	struct v4l2_mbus_framefmt pad_fmt;
 	unsigned int i, css_q;
-	int r;
+	int ret;
 	struct imgu_css_pipe *css_pipe = &imgu->css.pipes[pipe];
 	struct imgu_media_pipe *imgu_pipe = &imgu->imgu_pipe[pipe];
 	struct imgu_v4l2_subdev *imgu_sd = &imgu_pipe->imgu_sd;
 
-	dev_dbg(dev, "set fmt node [%u][%u](try = %d)", pipe, node, try);
+	dev_dbg(dev, "set fmt node [%u][%u](try = %u)", pipe, node, try);
 
 	for (i = 0; i < IMGU_NODE_NUM; i++)
-		dev_dbg(dev, "IMGU pipe %d node %d enabled = %d",
+		dev_dbg(dev, "IMGU pipe %u node %u enabled = %u",
 			pipe, i, imgu_pipe->nodes[i].enabled);
 
 	if (imgu_pipe->nodes[IMGU_NODE_VF].enabled)
@@ -688,7 +673,7 @@ static int imgu_fmt(struct imgu_device *imgu, unsigned int pipe, int node,
 	else
 		css_pipe->pipe_id = IPU3_CSS_PIPE_ID_CAPTURE;
 
-	dev_dbg(dev, "IPU3 pipe %d pipe_id = %d", pipe, css_pipe->pipe_id);
+	dev_dbg(dev, "IPU3 pipe %u pipe_id = %u", pipe, css_pipe->pipe_id);
 
 	for (i = 0; i < IPU3_CSS_QUEUES; i++) {
 		unsigned int inode = imgu_map_node(imgu, i);
@@ -698,9 +683,13 @@ static int imgu_fmt(struct imgu_device *imgu, unsigned int pipe, int node,
 			continue;
 
 		if (try) {
-			try_fmts[i] =
-				imgu_pipe->nodes[inode].vdev_fmt.fmt.pix_mp;
-			fmts[i] = &try_fmts[i];
+			fmts[i] = kmemdup(&imgu_pipe->nodes[inode].vdev_fmt.fmt.pix_mp,
+					  sizeof(struct v4l2_pix_format_mplane),
+					  GFP_KERNEL);
+			if (!fmts[i]) {
+				ret = -ENOMEM;
+				goto out;
+			}
 		} else {
 			fmts[i] = &imgu_pipe->nodes[inode].vdev_fmt.fmt.pix_mp;
 		}
@@ -730,26 +719,33 @@ static int imgu_fmt(struct imgu_device *imgu, unsigned int pipe, int node,
 	 * before we return success from this function, so set it here.
 	 */
 	css_q = imgu_node_to_queue(node);
-	if (fmts[css_q])
-		*fmts[css_q] = f->fmt.pix_mp;
-	else
-		return -EINVAL;
+	if (!fmts[css_q]) {
+		ret = -EINVAL;
+		goto out;
+	}
+	*fmts[css_q] = f->fmt.pix_mp;
 
 	if (try)
-		r = imgu_css_fmt_try(&imgu->css, fmts, rects, pipe);
+		ret = imgu_css_fmt_try(&imgu->css, fmts, rects, pipe);
 	else
-		r = imgu_css_fmt_set(&imgu->css, fmts, rects, pipe);
+		ret = imgu_css_fmt_set(&imgu->css, fmts, rects, pipe);
 
-	/* r is the binary number in the firmware blob */
-	if (r < 0)
-		return r;
+	/* ret is the binary number in the firmware blob */
+	if (ret < 0)
+		goto out;
 
 	if (try)
 		f->fmt.pix_mp = *fmts[css_q];
 	else
 		f->fmt = imgu_pipe->nodes[node].vdev_fmt.fmt;
 
-	return 0;
+out:
+	if (try) {
+		for (i = 0; i < IPU3_CSS_QUEUES; i++)
+			kfree(fmts[i]);
+	}
+
+	return ret;
 }
 
 static int imgu_try_fmt(struct file *file, void *fh, struct v4l2_format *f)
@@ -781,7 +777,7 @@ static int imgu_vidioc_try_fmt(struct file *file, void *fh,
 	struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
 	int r;
 
-	dev_dbg(dev, "%s [%ux%u] for node %d\n", __func__,
+	dev_dbg(dev, "%s [%ux%u] for node %u\n", __func__,
 		pix_mp->width, pix_mp->height, node->id);
 
 	r = imgu_try_fmt(file, fh, f);
@@ -799,7 +795,7 @@ static int imgu_vidioc_s_fmt(struct file *file, void *fh, struct v4l2_format *f)
 	struct v4l2_pix_format_mplane *pix_mp = &f->fmt.pix_mp;
 	int r;
 
-	dev_dbg(dev, "%s [%ux%u] for node %d\n", __func__,
+	dev_dbg(dev, "%s [%ux%u] for node %u\n", __func__,
 		pix_mp->width, pix_mp->height, node->id);
 
 	r = imgu_try_fmt(file, fh, f);
@@ -1022,7 +1018,7 @@ static int imgu_sd_s_ctrl(struct v4l2_ctrl *ctrl)
 	struct imgu_device *imgu = v4l2_get_subdevdata(&imgu_sd->subdev);
 	struct device *dev = &imgu->pci_dev->dev;
 
-	dev_dbg(dev, "set val %d to ctrl 0x%8x for subdev %d",
+	dev_dbg(dev, "set val %d to ctrl 0x%8x for subdev %u",
 		ctrl->val, ctrl->id, imgu_sd->pipe);
 
 	switch (ctrl->id) {
@@ -1122,7 +1118,7 @@ static int imgu_v4l2_subdev_register(struct imgu_device *imgu,
 	imgu_sd->subdev.flags = V4L2_SUBDEV_FL_HAS_DEVNODE |
 				V4L2_SUBDEV_FL_HAS_EVENTS;
 	snprintf(imgu_sd->subdev.name, sizeof(imgu_sd->subdev.name),
-		 "%s %d", IMGU_NAME, pipe);
+		 "%s %u", IMGU_NAME, pipe);
 	v4l2_set_subdevdata(&imgu_sd->subdev, imgu);
 	atomic_set(&imgu_sd->running_mode, IPU3_RUNNING_MODE_VIDEO);
 	v4l2_ctrl_handler_init(hdl, 1);
@@ -1240,7 +1236,7 @@ static int imgu_v4l2_node_setup(struct imgu_device *imgu, unsigned int pipe,
 	}
 
 	/* Initialize vdev */
-	snprintf(vdev->name, sizeof(vdev->name), "%s %d %s",
+	snprintf(vdev->name, sizeof(vdev->name), "%s %u %s",
 		 IMGU_NAME, pipe, node->name);
 	vdev->release = video_device_release_empty;
 	vdev->fops = &imgu_v4l2_fops;
@@ -1335,7 +1331,7 @@ static int imgu_v4l2_register_pipes(struct imgu_device *imgu)
 		r = imgu_v4l2_subdev_register(imgu, &imgu_pipe->imgu_sd, i);
 		if (r) {
 			dev_err(&imgu->pci_dev->dev,
-				"failed to register subdev%d ret (%d)\n", i, r);
+				"failed to register subdev%u ret (%d)\n", i, r);
 			goto pipes_cleanup;
 		}
 		r = imgu_v4l2_nodes_setup_pipe(imgu, i);
diff --git a/drivers/staging/media/ipu3/ipu3.c b/drivers/staging/media/ipu3/ipu3.c
index e0bbdad7cf5b..a7372395a101 100644
--- a/drivers/staging/media/ipu3/ipu3.c
+++ b/drivers/staging/media/ipu3/ipu3.c
@@ -236,6 +236,11 @@ int imgu_queue_buffers(struct imgu_device *imgu, bool initial, unsigned int pipe
 	dev_dbg(&imgu->pci_dev->dev, "Queue buffers to pipe %d", pipe);
 	mutex_lock(&imgu->lock);
 
+	if (!imgu_css_pipe_queue_empty(&imgu->css, pipe)) {
+		mutex_unlock(&imgu->lock);
+		return 0;
+	}
+
 	/* Buffer set is queued to FW only when input buffer is ready */
 	for (node = IMGU_NODE_NUM - 1;
 	     imgu_queue_getbuf(imgu, IMGU_NODE_IN, pipe);
@@ -245,6 +250,31 @@ int imgu_queue_buffers(struct imgu_device *imgu, bool initial, unsigned int pipe
 			dev_warn(&imgu->pci_dev->dev,
 				 "Vf not enabled, ignore queue");
 			continue;
+		} else if (node == IMGU_NODE_PARAMS &&
+			   imgu_pipe->nodes[node].enabled) {
+			struct vb2_buffer *vb;
+			struct imgu_vb2_buffer *ivb;
+
+			/* No parameters for this frame */
+			if (list_empty(&imgu_pipe->nodes[node].buffers))
+				continue;
+
+			ivb = list_first_entry(&imgu_pipe->nodes[node].buffers,
+					       struct imgu_vb2_buffer, list);
+			vb = &ivb->vbb.vb2_buf;
+			r = imgu_css_set_parameters(&imgu->css, pipe,
+						    vb2_plane_vaddr(vb, 0));
+			if (r) {
+				vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
+				dev_warn(&imgu->pci_dev->dev,
+					 "set parameters failed.");
+				continue;
+			}
+
+			vb2_buffer_done(vb, VB2_BUF_STATE_DONE);
+			dev_dbg(&imgu->pci_dev->dev,
+				"queue user parameters %d to css.", vb->index);
+			list_del(&ivb->list);
 		} else if (imgu_pipe->queue_enabled[node]) {
 			struct imgu_css_buffer *buf =
 				imgu_queue_getbuf(imgu, node, pipe);
@@ -790,7 +820,7 @@ out:
  * PCI rpm framework checks the existence of driver rpm callbacks.
  * Place a dummy callback here to avoid rpm going into error state.
  */
-static int imgu_rpm_dummy_cb(struct device *dev)
+static __maybe_unused int imgu_rpm_dummy_cb(struct device *dev)
 {
 	return 0;
 }