[alsa-devel] [alsa-lib][PATCH] ASoC: hdmi-codec: use unsigned type to structure members with bit-field instead of signed type
This is a fix for Linux 4.10-rc1.
In C language specification, a bit-field is interpreted as a signed or unsigned integer type consisting of the specified number of bits.
In GCC manual, the range of a signed bit field of N bits is from -(2^N) / 2 to ((2^N) / 2) - 1 https://www.gnu.org/software/gnu-c-manual/gnu-c-manual.html#Bit-Fields
Therefore, when defined as 1 bit-field with signed type, variables can represents -1 and 0.
The snd-soc-hdmi-codec module includes a structure which has signed type members with bit-fields. Codes of this module assign 0 and 1 to the members. This seems to result in implementation-dependent behaviours.
As of v4.10-rc1 merge window, outside of sound subsystem, this structure is referred by below GPU modules. - tda998x - sti-drm - mediatek-drm-hdmi - msm
As long as I review their codes relevant to the structure, the structure members are used just for condition statements and printk formats. My proposal of change is a bit intrusive to the printk formats but this may be acceptable.
Totally, it's reasonable to use unsigned type for the structure members. This bug is detected by Sparse, static code analyzer with below warnings.
./include/sound/hdmi-codec.h:39:26: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:40:28: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:41:29: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:42:31: error: dubious one-bit signed bitfield
CC: Jyri Sarha jsarha@ti.com CC: Jie Qiu jie.qiu@mediatek.com CC: Arnaud Pouliquen arnaud.pouliquen@st.com CC: Srinivas Kandagatla srinivas.kandagatla@linaro.org CC: dri-devel@lists.freedesktop.org CC: stable@vger.kernel.org Fixes: 09184118a8ab ("ASoC: hdmi-codec: Add hdmi-codec for external HDMI-encoders") Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp --- include/sound/hdmi-codec.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/sound/hdmi-codec.h b/include/sound/hdmi-codec.h index 530c57b..915c435 100644 --- a/include/sound/hdmi-codec.h +++ b/include/sound/hdmi-codec.h @@ -36,10 +36,10 @@ struct hdmi_codec_daifmt { HDMI_AC97, HDMI_SPDIF, } fmt; - int bit_clk_inv:1; - int frame_clk_inv:1; - int bit_clk_master:1; - int frame_clk_master:1; + unsigned int bit_clk_inv:1; + unsigned int frame_clk_inv:1; + unsigned int bit_clk_master:1; + unsigned int frame_clk_master:1; };
/*
Hi Takashi,
Reviewed and tested for sti machine.
Acked-by: Arnaud Pouliquen arnaud.pouliquen@st.com
Regards Arnaud
On 12/16/2016 10:26 AM, Takashi Sakamoto wrote:
This is a fix for Linux 4.10-rc1.
In C language specification, a bit-field is interpreted as a signed or unsigned integer type consisting of the specified number of bits.
In GCC manual, the range of a signed bit field of N bits is from -(2^N) / 2 to ((2^N) / 2) - 1 https://www.gnu.org/software/gnu-c-manual/gnu-c-manual.html#Bit-Fields
Therefore, when defined as 1 bit-field with signed type, variables can represents -1 and 0.
The snd-soc-hdmi-codec module includes a structure which has signed type members with bit-fields. Codes of this module assign 0 and 1 to the members. This seems to result in implementation-dependent behaviours.
As of v4.10-rc1 merge window, outside of sound subsystem, this structure is referred by below GPU modules.
- tda998x
- sti-drm
- mediatek-drm-hdmi
- msm
As long as I review their codes relevant to the structure, the structure members are used just for condition statements and printk formats. My proposal of change is a bit intrusive to the printk formats but this may be acceptable.
Totally, it's reasonable to use unsigned type for the structure members. This bug is detected by Sparse, static code analyzer with below warnings.
./include/sound/hdmi-codec.h:39:26: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:40:28: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:41:29: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:42:31: error: dubious one-bit signed bitfield
CC: Jyri Sarha jsarha@ti.com CC: Jie Qiu jie.qiu@mediatek.com CC: Arnaud Pouliquen arnaud.pouliquen@st.com CC: Srinivas Kandagatla srinivas.kandagatla@linaro.org CC: dri-devel@lists.freedesktop.org CC: stable@vger.kernel.org Fixes: 09184118a8ab ("ASoC: hdmi-codec: Add hdmi-codec for external HDMI-encoders") Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp
include/sound/hdmi-codec.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/sound/hdmi-codec.h b/include/sound/hdmi-codec.h index 530c57b..915c435 100644 --- a/include/sound/hdmi-codec.h +++ b/include/sound/hdmi-codec.h @@ -36,10 +36,10 @@ struct hdmi_codec_daifmt { HDMI_AC97, HDMI_SPDIF, } fmt;
- int bit_clk_inv:1;
- int frame_clk_inv:1;
- int bit_clk_master:1;
- int frame_clk_master:1;
- unsigned int bit_clk_inv:1;
- unsigned int frame_clk_inv:1;
- unsigned int bit_clk_master:1;
- unsigned int frame_clk_master:1;
};
/*
Oops. This is not a patch for alsa-lib, but for Linux kernel. I'm sorry to confuse you...
On Dec 16 2016 18:26, Takashi Sakamoto wrote:
This is a fix for Linux 4.10-rc1.
In C language specification, a bit-field is interpreted as a signed or unsigned integer type consisting of the specified number of bits.
In GCC manual, the range of a signed bit field of N bits is from -(2^N) / 2 to ((2^N) / 2) - 1 https://www.gnu.org/software/gnu-c-manual/gnu-c-manual.html#Bit-Fields
Therefore, when defined as 1 bit-field with signed type, variables can represents -1 and 0.
The snd-soc-hdmi-codec module includes a structure which has signed type members with bit-fields. Codes of this module assign 0 and 1 to the members. This seems to result in implementation-dependent behaviours.
As of v4.10-rc1 merge window, outside of sound subsystem, this structure is referred by below GPU modules.
- tda998x
- sti-drm
- mediatek-drm-hdmi
- msm
As long as I review their codes relevant to the structure, the structure members are used just for condition statements and printk formats. My proposal of change is a bit intrusive to the printk formats but this may be acceptable.
Totally, it's reasonable to use unsigned type for the structure members. This bug is detected by Sparse, static code analyzer with below warnings.
./include/sound/hdmi-codec.h:39:26: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:40:28: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:41:29: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:42:31: error: dubious one-bit signed bitfield
CC: Jyri Sarha jsarha@ti.com CC: Jie Qiu jie.qiu@mediatek.com CC: Arnaud Pouliquen arnaud.pouliquen@st.com CC: Srinivas Kandagatla srinivas.kandagatla@linaro.org CC: dri-devel@lists.freedesktop.org CC: stable@vger.kernel.org Fixes: 09184118a8ab ("ASoC: hdmi-codec: Add hdmi-codec for external HDMI-encoders") Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp
include/sound/hdmi-codec.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/sound/hdmi-codec.h b/include/sound/hdmi-codec.h index 530c57b..915c435 100644 --- a/include/sound/hdmi-codec.h +++ b/include/sound/hdmi-codec.h @@ -36,10 +36,10 @@ struct hdmi_codec_daifmt { HDMI_AC97, HDMI_SPDIF, } fmt;
- int bit_clk_inv:1;
- int frame_clk_inv:1;
- int bit_clk_master:1;
- int frame_clk_master:1;
- unsigned int bit_clk_inv:1;
- unsigned int frame_clk_inv:1;
- unsigned int bit_clk_master:1;
- unsigned int frame_clk_master:1;
};
/*
Regards
Takashi Sakamoto
On Fri, Dec 16, 2016 at 06:26:54PM +0900, Takashi Sakamoto wrote:
This is a fix for Linux 4.10-rc1.
This...
CC: stable@vger.kernel.org Fixes: 09184118a8ab ("ASoC: hdmi-codec: Add hdmi-codec for external HDMI-encoders")
...and this don't add up (though it is something that should go to stable, good catch). Please also try to keep your subject lines much shorter.
The patch
ASoC: hdmi-codec: use unsigned type to structure members with bit-field
has been applied to the asoc tree at
git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git
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
From 9e4d59ada4d602e78eee9fb5f898ce61fdddb446 Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto o-takashi@sakamocchi.jp Date: Fri, 16 Dec 2016 18:26:54 +0900 Subject: [PATCH] ASoC: hdmi-codec: use unsigned type to structure members with bit-field
This is a fix for Linux 4.10-rc1.
In C language specification, a bit-field is interpreted as a signed or unsigned integer type consisting of the specified number of bits.
In GCC manual, the range of a signed bit field of N bits is from -(2^N) / 2 to ((2^N) / 2) - 1 https://www.gnu.org/software/gnu-c-manual/gnu-c-manual.html#Bit-Fields
Therefore, when defined as 1 bit-field with signed type, variables can represents -1 and 0.
The snd-soc-hdmi-codec module includes a structure which has signed type members with bit-fields. Codes of this module assign 0 and 1 to the members. This seems to result in implementation-dependent behaviours.
As of v4.10-rc1 merge window, outside of sound subsystem, this structure is referred by below GPU modules. - tda998x - sti-drm - mediatek-drm-hdmi - msm
As long as I review their codes relevant to the structure, the structure members are used just for condition statements and printk formats. My proposal of change is a bit intrusive to the printk formats but this may be acceptable.
Totally, it's reasonable to use unsigned type for the structure members. This bug is detected by Sparse, static code analyzer with below warnings.
./include/sound/hdmi-codec.h:39:26: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:40:28: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:41:29: error: dubious one-bit signed bitfield ./include/sound/hdmi-codec.h:42:31: error: dubious one-bit signed bitfield
Fixes: 09184118a8ab ("ASoC: hdmi-codec: Add hdmi-codec for external HDMI-encoders") Signed-off-by: Takashi Sakamoto o-takashi@sakamocchi.jp Acked-by: Arnaud Pouliquen arnaud.pouliquen@st.com Signed-off-by: Mark Brown broonie@kernel.org CC: stable@vger.kernel.org --- include/sound/hdmi-codec.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/sound/hdmi-codec.h b/include/sound/hdmi-codec.h index 530c57bdefa0..915c4357945c 100644 --- a/include/sound/hdmi-codec.h +++ b/include/sound/hdmi-codec.h @@ -36,10 +36,10 @@ struct hdmi_codec_daifmt { HDMI_AC97, HDMI_SPDIF, } fmt; - int bit_clk_inv:1; - int frame_clk_inv:1; - int bit_clk_master:1; - int frame_clk_master:1; + unsigned int bit_clk_inv:1; + unsigned int frame_clk_inv:1; + unsigned int bit_clk_master:1; + unsigned int frame_clk_master:1; };
/*
participants (3)
-
Arnaud Pouliquen -
Mark Brown -
Takashi Sakamoto