[PATCH] ASoC: Fix overflow bug in SOC_DOUBLE_R_SX_TLV
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From: Stuart Longland on 17 Jun 2010 23:00 When SX_TLV widgets are read, if the gain is set to a value below 0dB, the mixer control is erroniously read as being at maximum volume. The value read out of the CODEC register is never sign-extended, and when the minimum value is subtracted (read; added, since the minimum is negative) the result is a number greater than the maximum allowed value for the control, and hence it saturates. Solution: Mask the result so that it "wraps around", emulating sign-extension. Signed-off-by: Stuart Longland <redhatter(a)gentoo.org> --- sound/soc/soc-core.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index a82a797..0470288 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -2400,8 +2400,8 @@ int snd_soc_get_volsw_2r_sx(struct snd_kcontrol *kcontrol, int val = snd_soc_read(codec, mc->reg) & mask; int valr = snd_soc_read(codec, mc->rreg) & mask; - ucontrol->value.integer.value[0] = ((val & 0xff)-min); - ucontrol->value.integer.value[1] = ((valr & 0xff)-min); + ucontrol->value.integer.value[0] = ((val & 0xff)-min) & mask; + ucontrol->value.integer.value[1] = ((valr & 0xff)-min) & mask; return 0; } EXPORT_SYMBOL_GPL(snd_soc_get_volsw_2r_sx); -- 1.6.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |