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

[Pierre-Louis Bossart]

>>> Build time dependencies aren't going to help anything, arm64 (and to my
>>> understanding some future x86 systems, LynxPoint IIRC) supports both DT
>>> and ACPI and so you have kernels built with support for both.
> 
>> well, that's what I suggested initially:
>>         if (is_of_node(card->dev->fwnode))
> 
>> I used the of_node test as a proxy for 'no DMI' since I am not aware of any
>> means to detect if DMI is enabled at run-time.
> 
> Can we not fix the DMI code so it lets us check dmi_available either
> directly or with an accessor?  I don't understand why all the proposals
> are dancing around local bodges here.

something like this then (compile-tested only)?

diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index d51ca0428bb8..f191a1f901ac 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -166,6 +166,7 @@ static int __init dmi_checksum(const u8 *buf, u8 len)
  static const char *dmi_ident[DMI_STRING_MAX];
  static LIST_HEAD(dmi_devices);
  int dmi_available;
+EXPORT_SYMBOL_GPL(dmi_available);

  /*
   *     Save a DMI string
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 16ba54eb8164..c7e4600b2dd4 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -1574,7 +1574,7 @@ 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))
+       if (!dmi_available)
                 return 0;

         /* make up dmi long name as: vendor-product-version-board */