From: Phil Elwell <phil@xxxxxxxxxxxxxxx> commit db2b927f8668adf3ac765e0921cd2720f5c04172 upstream. The dmas property is used to hold the dmaengine channel used for audio output. Older device trees were missing that property, so if it's not there we disable the audio output entirely. However, some overlays have set an empty value to that property, mostly to workaround the fact that overlays cannot remove a property. Let's add a test for that case and if it's empty, let's disable it as well. Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Phil Elwell <phil@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220613144800.326124-18-maxime@xxxxxxxxxx Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/vc4/vc4_hdmi.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -1231,12 +1231,12 @@ static int vc4_hdmi_audio_init(struct vc struct snd_soc_card *card = &vc4_hdmi->audio.card; struct device *dev = &vc4_hdmi->pdev->dev; const __be32 *addr; - int index; + int index, len; int ret; - if (!of_find_property(dev->of_node, "dmas", NULL)) { + if (!of_find_property(dev->of_node, "dmas", &len) || !len) { dev_warn(dev, - "'dmas' DT property is missing, no HDMI audio\n"); + "'dmas' DT property is missing or empty, no HDMI audio\n"); return 0; }
