The rcar sound driver uses regmap to access registers in various parts of the block and uses regmap to manage mappings. The regmap is created without fast_io set, which means it locks with a mutex rather than a lighter-spinlock.
The use of the mutex lock causes issues when the IRQ handler is entered as the code needs to read/write register values and thus with lock debugging enabled the system outputs a number of warnings such as:
BUG: sleeping function called from invalid context at rnel/locking/mutex.c:616
The rcar registers are all connected via APB bus and thus not that slow to access. The fix is to set the fast_io in the code so that regmap creates the regmap structures using the faster spinlock functions.
Signed-off-by: Ben Dooks ben.dooks@codethink.co.uk --- sound/soc/sh/rcar/gen.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/sound/soc/sh/rcar/gen.c b/sound/soc/sh/rcar/gen.c index 9094970..6468962 100644 --- a/sound/soc/sh/rcar/gen.c +++ b/sound/soc/sh/rcar/gen.c @@ -66,6 +66,7 @@ static int rsnd_regmap_read32(void *context, }
static struct regmap_bus rsnd_regmap_bus = { + .fast_io = true, .write = rsnd_regmap_write32, .read = rsnd_regmap_read32, .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,