[alsa-devel] [PATCH 1/9] ALSA: usb-audio: UAC2: clean up parsing of bmaControls

[Takashi Iwai]

At Mon, 31 May 2010 13:35:36 +0200,
Daniel Mack wrote:
> 
> Introduce two new static inline functions for a more readable parsing
> of UAC2 bmaControls.
> 
> Signed-off-by: Daniel Mack <daniel at caiaq.de>

Thanks!  Now I applied all patches for 2.6.35-rc2.

But, basically I don't want to touch too much after this.
So, please avoid refactoring patches for 2.6.35.  If any, prepare a
separate one for 2.6.36, and let's concentrate on fixes during
2.6.35-rc.


Takashi

> ---
>  include/linux/usb/audio-v2.h |   10 ++++++++++
>  sound/usb/mixer.c            |    8 ++++----
>  2 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/usb/audio-v2.h b/include/linux/usb/audio-v2.h
> index 92f1d99..8f91be3 100644
> --- a/include/linux/usb/audio-v2.h
> +++ b/include/linux/usb/audio-v2.h
> @@ -18,6 +18,16 @@
>  /* v1.0 and v2.0 of this standard have many things in common. For the rest
>   * of the definitions, please refer to audio.h */
>  
> +static inline bool uac2_control_is_readable(u32 bmControls, u8 control)
> +{
> +	return (bmControls >> (control * 2)) & 0x1;
> +}
> +
> +static inline bool uac2_control_is_writeable(u32 bmControls, u8 control)
> +{
> +	return (bmControls >> (control * 2)) & 0x2;
> +}
> +
>  /* 4.7.2.1 Clock Source Descriptor */
>  
>  struct uac_clock_source_descriptor {
> diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
> index 03ce971..43d6417 100644
> --- a/sound/usb/mixer.c
> +++ b/sound/usb/mixer.c
> @@ -1188,9 +1188,9 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
>  
>  			for (j = 0; j < channels; j++) {
>  				unsigned int mask = snd_usb_combine_bytes(bmaControls + csize * (j+1), csize);
> -				if (mask & (1 << (i * 2))) {
> +				if (uac2_control_is_readable(mask, i)) {
>  					ch_bits |= (1 << j);
> -					if (~mask & (1 << ((i * 2) + 1)))
> +					if (!uac2_control_is_writeable(mask, i))
>  						ch_read_only |= (1 << j);
>  				}
>  			}
> @@ -1198,9 +1198,9 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
>  			/* FIXME: the whole unit is read-only if any of the channels is marked read-only */
>  			if (ch_bits & 1) /* the first channel must be set (for ease of programming) */
>  				build_feature_ctl(state, _ftr, ch_bits, i, &iterm, unitid, !!ch_read_only);
> -			if (master_bits & (1 << i * 2))
> +			if (uac2_control_is_readable(master_bits, i))
>  				build_feature_ctl(state, _ftr, 0, i, &iterm, unitid,
> -						  ~master_bits & (1 << ((i * 2) + 1)));
> +						  !uac2_control_is_writeable(master_bits, i));
>  		}
>  	}
>  
> -- 
> 1.7.1
>