[alsa-devel] [PATCH] ASoC: tegra: Use flat regcache.

[Dylan Reid]

On Mon, Mar 17, 2014 at 9:07 PM, Andrew Bresticker
<abrestic at chromium.org> wrote:
>> When using an rbtree cache, there can be allocations the first time a
>> register is accessed.  This can cause an attempt to schedule while
>> atomic in the case that the regmap is using a spinlock.  This could be
>> fixed by either initializing all the registers or using a flat cache.
>> The register maps for tegra30_ahub and tegra30_i2s are dense and don't
>> save much from using a tree so convert them to flat.
>
> Looks like the Tegra20 drivers have the same issue as well.

Correct, I can tack those on too. I couldn't find a tegra20 board that
boots to test on, so that part will only get compile tested.

>
> -Andrew
>
>>
>> Signed-off-by: Dylan Reid <dgreid at chromium.org>
>> ---
>>  sound/soc/tegra/tegra30_ahub.c | 4 ++--
>>  sound/soc/tegra/tegra30_i2s.c  | 2 +-
>>  2 files changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/sound/soc/tegra/tegra30_ahub.c b/sound/soc/tegra/tegra30_ahub.c
>> index d6f4c99..0db68f4 100644
>> --- a/sound/soc/tegra/tegra30_ahub.c
>> +++ b/sound/soc/tegra/tegra30_ahub.c
>> @@ -471,7 +471,7 @@ static const struct regmap_config tegra30_ahub_apbif_regmap_config = {
>>         .readable_reg = tegra30_ahub_apbif_wr_rd_reg,
>>         .volatile_reg = tegra30_ahub_apbif_volatile_reg,
>>         .precious_reg = tegra30_ahub_apbif_precious_reg,
>> -       .cache_type = REGCACHE_RBTREE,
>> +       .cache_type = REGCACHE_FLAT,
>>  };
>>
>>  static bool tegra30_ahub_ahub_wr_rd_reg(struct device *dev, unsigned int reg)
>> @@ -490,7 +490,7 @@ static const struct regmap_config tegra30_ahub_ahub_regmap_config = {
>>         .max_register = LAST_REG(AUDIO_RX),
>>         .writeable_reg = tegra30_ahub_ahub_wr_rd_reg,
>>         .readable_reg = tegra30_ahub_ahub_wr_rd_reg,
>> -       .cache_type = REGCACHE_RBTREE,
>> +       .cache_type = REGCACHE_FLAT,
>>  };
>>
>>  static struct tegra30_ahub_soc_data soc_data_tegra30 = {
>> diff --git a/sound/soc/tegra/tegra30_i2s.c b/sound/soc/tegra/tegra30_i2s.c
>> index 49ad936..f146c41 100644
>> --- a/sound/soc/tegra/tegra30_i2s.c
>> +++ b/sound/soc/tegra/tegra30_i2s.c
>> @@ -357,7 +357,7 @@ static const struct regmap_config tegra30_i2s_regmap_config = {
>>         .writeable_reg = tegra30_i2s_wr_rd_reg,
>>         .readable_reg = tegra30_i2s_wr_rd_reg,
>>         .volatile_reg = tegra30_i2s_volatile_reg,
>> -       .cache_type = REGCACHE_RBTREE,
>> +       .cache_type = REGCACHE_FLAT,
>>  };
>>
>>  static const struct tegra30_i2s_soc_data tegra30_i2s_config = {
>> --
>> 1.8.1.3.605.g02339dd
>>