[PATCH V2] ASoC: soc-core: Prevent warning if no DMI table is present

[Jon Hunter <jonathanh@nvidia.com>]

Many systems do not use ACPI and hence do not provide a DMI table. On
non-ACPI systems a warning, such as the following, is printed on boot.

 WARNING KERN tegra-audio-graph-card sound: ASoC: no DMI vendor name!

The variable 'dmi_available' is not exported and so currently cannot be
used by kernel modules without adding an accessor. However, it is
possible to use the function is_acpi_device_node() to determine if the
sound card is an ACPI device and hence indicate if we expect a DMI table
to be present. Therefore, call is_acpi_device_node() to see if we are
using ACPI and only parse the DMI table if we are booting with ACPI.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
Changes since V1:
- Use is_acpi_device_node() to determine if we expect the DMI table to
  be present.

 sound/soc/soc-core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index f6d4e99b590c..0cffc9527e28 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -31,6 +31,7 @@
 #include <linux/of.h>
 #include <linux/of_graph.h>
 #include <linux/dmi.h>
+#include <linux/acpi.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -1573,6 +1574,9 @@ int snd_soc_set_dmi_name(struct snd_soc_card *card, const char *flavour)
 	if (card->long_name)
 		return 0; /* long name already set by driver or from DMI */
 
+	if (!is_acpi_device_node(card->dev->fwnode))
+		return 0;
+
 	/* make up dmi long name as: vendor-product-version-board */
 	vendor = dmi_get_system_info(DMI_BOARD_VENDOR);
 	if (!vendor || !is_dmi_valid(vendor)) {
-- 
2.25.1