[media.git/next] media: v4l2-common: Reduce warnings about missing V4L2_CID_LINK_FREQ control

[media-ci]

On Thu May 8 10:37:45 2025 +0200, Niklas Söderlund wrote:
> When operating a pipeline with a missing V4L2_CID_LINK_FREQ control this
> two line warning is printed each time the pipeline is started. Reduce
> this excessive logging by only warning once for the missing control.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund+rene...@ragnatech.se>
> Signed-off-by: Sakari Ailus <sakari.ai...@linux.intel.com>
> Signed-off-by: Hans Verkuil <hverk...@xs4all.nl>

Patch committed.

Thanks,
Hans Verkuil

 drivers/media/v4l2-core/v4l2-common.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

---

diff --git a/drivers/media/v4l2-core/v4l2-common.c 
b/drivers/media/v4l2-core/v4l2-common.c
index bd160a8c9efe..e1fc8fe43b74 100644
--- a/drivers/media/v4l2-core/v4l2-common.c
+++ b/drivers/media/v4l2-core/v4l2-common.c
@@ -505,10 +505,10 @@ s64 __v4l2_get_link_freq_ctrl(struct v4l2_ctrl_handler 
*handler,
 
                freq = div_u64(v4l2_ctrl_g_ctrl_int64(ctrl) * mul, div);
 
-               pr_warn("%s: Link frequency estimated using pixel rate: result 
might be inaccurate\n",
-                       __func__);
-               pr_warn("%s: Consider implementing support for 
V4L2_CID_LINK_FREQ in the transmitter driver\n",
-                       __func__);
+               pr_warn_once("%s: Link frequency estimated using pixel rate: 
result might be inaccurate\n",
+                            __func__);
+               pr_warn_once("%s: Consider implementing support for 
V4L2_CID_LINK_FREQ in the transmitter driver\n",
+                            __func__);
        }
 
        return freq > 0 ? freq : -EINVAL;