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: 09184118a8 ("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
Current hdmi-codec driver is assuming that it will be registered
from HDMI driver. Because of this assumption, each callback function
has struct device pointer which is parent device (= HDMI).
Then, it can use dev_get_drvdata() to get private data.
OTOH, on some SoC/HDMI case, SoC has VIDEO/SOUND and HDMI IPs.
This case, it needs SoC VIDEO, SoC SOUND and HDMI video, HDMI codec
driver. In DesignWare HDMI IP case, SoC VIDEO (= DRM/KMS) driver tries
to bind DesignWare HDMI video driver, and HDMI codec driver
(= hdmi-codec). This case, above "parent device" of HDMI codec driver
is DRM/KMS driver and its "device" already has private data.
And, from DT and ASoC CPU/Codec/Card binding point of view, HDMI codec
(= hdmi-codec) needs to have "parent device" (= DRM/KMS), otherwise,
it never detect sound card.
Because of these reasons, some driver can't use dev_get_drvdata() to
get private data on hdmi-codec driver. This patch add new void pointer
on hdmi_codec_pdata for private data, and callback function will be
called with it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
The hdmi-codec is a platform device driver to be registered from
drivers of external HDMI encoders with I2S and/or spdif interface. The
driver in turn registers an ASoC codec for the HDMI encoder's audio
functionality.
The structures and definitions in the API header are mostly redundant
copies of similar structures in ASoC headers. This is on purpose to
avoid direct dependencies to ASoC structures in video side driver.
Signed-off-by: Jyri Sarha <jsarha@ti.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Acked-by: PC Liao <pc.liao@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Takashi Sakamoto