Re: [PATCH] usb-audio: fix combine_word problem

[Takashi Iwai <tiwai@suse.de>]

At Fri, 6 Nov 2009 23:44:53 +0200 (EET),
Julian Anastasov wrote:
> 
> 
> 	Fix combine_word problem where first octet is not
> read properly. The only affected place seems to be the
> INPUT_TERMINAL type. Before now, sound controls can be created
> with the output terminal's name which is a fallback mechanism
> used only for unknown input terminal types. For example,
> Line can wrongly appear as Speaker. After the change it
> should appear as Line.

Wow, this is really an old bug.  I wonder no one noticed it, so far...

> 	The side effect of this change can be that users
> can expect the wrong control name in their scripts or
> programs while now we return the correct one.

Yes, but it's a right "fix", so let it be.

> 	Probably, these defines should use get_unaligned_le16 and
> friends.

Sounds like a good idea.  But 24bit version is still missing :)

> Signed-off-by: Julian Anastasov <ja@ssi.bg>

Applied now, and added Cc to stable kernel.

Thanks!


Takashi

> ---
> 
> diff -urp v2.6.31/linux/sound/usb/usbaudio.h linux/sound/usb/usbaudio.h
> --- v2.6.31/linux/sound/usb/usbaudio.h	2009-06-13 10:53:59.000000000 +0300
> +++ linux/sound/usb/usbaudio.h	2009-11-06 22:38:00.000000000 +0200
> @@ -210,7 +210,7 @@ struct snd_usb_midi_endpoint_info {
>  /*
>   */
>  
> -#define combine_word(s)    ((*s) | ((unsigned int)(s)[1] << 8))
> +#define combine_word(s)    ((*(s)) | ((unsigned int)(s)[1] << 8))
>  #define combine_triple(s)  (combine_word(s) | ((unsigned int)(s)[2] << 16))
>  #define combine_quad(s)    (combine_triple(s) | ((unsigned int)(s)[3] << 24))
>  
>