[PATCH v2 0/3] ALSA: Fix compiler warnings in sound subsystem

[PATCH v2 0/3] ALSA: Fix compiler warnings in sound subsystem

[wangdich9700]

From: wangdicheng <wangdicheng@kylinos.cn>

This series fixes three compiler warnings in the sound subsystem,
covering both logical redundancies and a potential runtime bug.

Two categories of warnings are addressed:

1. "possible condition with no effect (if == else)" -- redundant
   conditional branches that produce identical code.

2. "do_div() does a 64-by-32 division" -- use of do_div() with
   a 64-bit divisor, which silently truncates the upper 32 bits.

Changes in v2:
- Dropped "ASoC: tlv320aic32x4: Use div64_ul for division by unsigned long".
  Per David's review, parent_rate is bounded by AIC32X4_MAX_PLL_CLKIN
  (20MHz) and will never exceed 32 bits, so do_div() is fine there.
- Updated patch 3 (fsl_easrc) commit message with concrete numerical
  proof that val1 can exceed 32 bits after >> 12, and clarified that
  the truncation happens when val1 is used as a divisor.

wangdicheng (3):
  ASoC: mediatek: mt8189: Remove redundant else-if branch with identical
    body
  ALSA: sparc/dbri: Fix "possible condition with no effect" warning
  ASoC: fsl_easrc: Use div64_u64 for 64-by-64 division

 sound/soc/fsl/fsl_easrc.c                   | 2 +-
 sound/soc/mediatek/mt8189/mt8189-dai-adda.c | 2 --
 sound/sparc/dbri.c                          | 2 ++
 3 files changed, 3 insertions(+), 3 deletions(-)

-- 
2.25.1

[PATCH v2 1/3] ASoC: mediatek: mt8189: Remove redundant else-if branch with identical body

[wangdich9700]

From: wangdicheng <wangdicheng@kylinos.cn>

Fix a compiler warning about a condition with no effect:

sound/mediatek/mt8189/mt8189-dai-adda.c:388:7-9: WARNING: possible condition with no effect (if == else)

The MTKAIF_PROTOCOL_2 branch and the else branch both write the same
value 0xB0 to AFE_AUD_PAD_TOP_CFG0, making the else-if condition
meaningless. Remove the redundant branch.

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
---
 sound/soc/mediatek/mt8189/mt8189-dai-adda.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/sound/soc/mediatek/mt8189/mt8189-dai-adda.c b/sound/soc/mediatek/mt8189/mt8189-dai-adda.c
index ad5b9546ff63..5c41a6386204 100644
--- a/sound/soc/mediatek/mt8189/mt8189-dai-adda.c
+++ b/sound/soc/mediatek/mt8189/mt8189-dai-adda.c
@@ -385,8 +385,6 @@ static int mtk_adda_pad_top_event(struct snd_soc_dapm_widget *w,
 	if (event == SND_SOC_DAPM_PRE_PMU) {
 		if (afe_priv->mtkaif_protocol == MTKAIF_PROTOCOL_2_CLK_P2)
 			regmap_write(afe->regmap, AFE_AUD_PAD_TOP_CFG0, 0xB8);
-		else if (afe_priv->mtkaif_protocol == MTKAIF_PROTOCOL_2)
-			regmap_write(afe->regmap, AFE_AUD_PAD_TOP_CFG0, 0xB0);
 		else
 			regmap_write(afe->regmap, AFE_AUD_PAD_TOP_CFG0, 0xB0);
 	}
-- 
2.25.1

[PATCH v2 2/3] ALSA: sparc/dbri: Fix "possible condition with no effect" warning

[wangdich9700]

From: wangdicheng <wangdicheng@kylinos.cn>

Fix a compiler warning about a condition with no effect:

sound/sparc/dbri.c:1843:1-3: WARNING: possible condition with no effect (if == else)

When DBRI_DEBUG is not defined, dprintk expands to an empty do-while
statement, making both branches of the if-else no-ops. Guard the entire
debug block with #ifdef DBRI_DEBUG to eliminate the warning and keep
the rval reference consistent with its declaration scope.

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
---
 sound/sparc/dbri.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/sparc/dbri.c b/sound/sparc/dbri.c
index 2f5f62079fa4..ccaa36525f8d 100644
--- a/sound/sparc/dbri.c
+++ b/sound/sparc/dbri.c
@@ -1840,6 +1840,7 @@ static void dbri_process_one_interrupt(struct snd_dbri *dbri, int x)
 	int rval = D_INTR_GETRVAL(x);
 #endif
 
+#ifdef DBRI_DEBUG
 	if (channel == D_INTR_CMD) {
 		dprintk(D_CMD, "INTR: Command: %-5s  Value:%d\n",
 			cmds[command], val);
@@ -1847,6 +1848,7 @@ static void dbri_process_one_interrupt(struct snd_dbri *dbri, int x)
 		dprintk(D_INT, "INTR: Chan:%d Code:%d Val:%#x\n",
 			channel, code, rval);
 	}
+#endif
 
 	switch (code) {
 	case D_INTR_CMDI:
-- 
2.25.1

Re: [PATCH v2 2/3] ALSA: sparc/dbri: Fix "possible condition with no effect" warning

[Takashi Iwai]

On Fri, 17 Jul 2026 11:15:41 +0200,
wangdich9700@163.com wrote:
> 
> From: wangdicheng <wangdicheng@kylinos.cn>
> 
> Fix a compiler warning about a condition with no effect:
> 
> sound/sparc/dbri.c:1843:1-3: WARNING: possible condition with no effect (if == else)
> 
> When DBRI_DEBUG is not defined, dprintk expands to an empty do-while
> statement, making both branches of the if-else no-ops. Guard the entire
> debug block with #ifdef DBRI_DEBUG to eliminate the warning and keep
> the rval reference consistent with its declaration scope.
> 
> Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>

Applied to for-next branch.  Thanks.


Takashi

[PATCH v2 3/3] ASoC: fsl_easrc: Use div64_u64 for 64-by-64 division

[wangdich9700]

From: wangdicheng <wangdicheng@kylinos.cn>

Fix a coccinelle warning about do_div() truncating a 64-bit divisor:

sound/soc/fsl/fsl_easrc.c:2061:2-8: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead.

In fsl_easrc_m2m_calc_out_len(), val1 is computed as:

  val1 = (u64)in_rate << frac_bits;   // frac_bits up to 39
  do_div(val1, out_rate);
  val1 += (s64)ctx_priv->ratio_mod << (frac_bits - 31);
  val1 = val1 >> 12;

In the worst case (in_rate=384000, out_rate=8000, frac_bits=39):
  val1 = 384000 << 39 / 8000 = 26,388,279,068,672
  val1 >> 12 = 6,440,497,829  (33 bits, exceeds 32-bit range)

val1 is then used as the divisor in do_div(val2, val1), where
do_div() silently truncates it to 32 bits, producing incorrect
results. Use div64_u64() to perform a proper 64-by-64 division.

Fixes: 955ac624058f ("ASoC: fsl_easrc: Add EASRC ASoC CPU DAI drivers")
Cc: stable@vger.kernel.org
Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
---
 sound/soc/fsl/fsl_easrc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/fsl/fsl_easrc.c b/sound/soc/fsl/fsl_easrc.c
index 114a6c0b6b73..d0bbe9f71e36 100644
--- a/sound/soc/fsl/fsl_easrc.c
+++ b/sound/soc/fsl/fsl_easrc.c
@@ -2058,7 +2058,7 @@ static int fsl_easrc_m2m_calc_out_len(struct fsl_asrc_pair *pair, int input_buff
 		/* right shift 12 bit to make ratio in 32bit space */
 		val2 = (u64)in_samples << (frac_bits - 12);
 		val1 = val1 >> 12;
-		do_div(val2, val1);
+		val2 = div64_u64(val2, val1);
 		out_samples = val2;
 
 		out_length = out_samples * out_width * channels;
-- 
2.25.1

Re: (subset) [PATCH v2 0/3] ALSA: Fix compiler warnings in sound subsystem

[Mark Brown]

On Fri, 17 Jul 2026 17:15:39 +0800, wangdich9700@163.com wrote:
> ALSA: Fix compiler warnings in sound subsystem
> 
> From: wangdicheng <wangdicheng@kylinos.cn>
> 
> This series fixes three compiler warnings in the sound subsystem,
> covering both logical redundancies and a potential runtime bug.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-7.3

Thanks!

[1/3] ASoC: mediatek: mt8189: Remove redundant else-if branch with identical body
      https://git.kernel.org/broonie/sound/c/fcf2a365da23
[3/3] ASoC: fsl_easrc: Use div64_u64 for 64-by-64 division
      https://git.kernel.org/broonie/sound/c/a46ccc71877e

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark