[PATCH] ASoC: topology: Select SND_DYNAMIC_MINORS

[Pierre-Louis Bossart]

From: Peter Ujfalusi <peter.ujfalusi at linux.intel.com>

The indexes of the devices are described within the topology file, it is a
possibility that the topology encodes invalid indexes when DYNAMIC_MINORS
is not enabled in kernel:

 #define SNDRV_MINOR_COMPRESS		2	/* 2 - 3 */
 #define SNDRV_MINOR_HWDEP		4	/* 4 - 7 */
 #define SNDRV_MINOR_RAWMIDI		8	/* 8 - 15 */
 #define SNDRV_MINOR_PCM_PLAYBACK	16	/* 16 - 23 */
 #define SNDRV_MINOR_PCM_CAPTURE	24	/* 24 - 31 */

If the topology assigns an index greater than 7 for PLAYBACK/CAPTURE PCM
then there will be minor number collision.

As an example:
card0 creates a capture PCM with index 10 -> minor = 34
card1 creates compress device with index 0 -> minor = 34

Card1 will fail to instantiate because the minor for the compress stream is
already taken.

To avoid seemingly mysterious issues with card creation, select the
DYNAMIC_MINORS when the topology is enabled.

The other option would be to try to do out of bound index checks in case of
DYNAMIC_MINOR is not enabled and do not even attempt to create the device
with failing the topology load.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi at linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 sound/soc/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sound/soc/Kconfig b/sound/soc/Kconfig
index 8a13462e1a63..5dcf77af07af 100644
--- a/sound/soc/Kconfig
+++ b/sound/soc/Kconfig
@@ -36,6 +36,7 @@ config SND_SOC_COMPRESS
 
 config SND_SOC_TOPOLOGY
 	bool
+	select SND_DYNAMIC_MINORS
 
 config SND_SOC_TOPOLOGY_KUNIT_TEST
 	tristate "KUnit tests for SoC topology"
-- 
2.25.1