Subject: Re: linux-next: build failure after merge of the akpm tree

From: Andrew Morton <[email-masked]>
Date: Fri, 15 Jan 2016 15:14:01 -0800

On Sat, 16 Jan 2016 10:00:47 +1100 Stephen Rothwell <[email-masked]> wrote:

> Hi Andrew,
> > +#define SNDRV_COMPRESS_GET_CODEC_CAPS	_IOWR('C', 0x11, struct snd_compr_caps)
> >  #define SNDRV_COMPRESS_SET_PARAMS	_IOW('C', 0x12, struct snd_compr_params)
> >  #define SNDRV_COMPRESS_GET_PARAMS	_IOR('C', 0x13, struct snd_codec)
> >  #define SNDRV_COMPRESS_SET_METADATA	_IOW('C', 0x14,\
> > 
> > then it compiles OK.  So there's something special about `struct
> > snd_compr_codec_caps' which is confusing the compiler.
> 
> Its very big (hint, I think it is bigger than 1 << 13).

ah-hah.

sizeof(struct snd_compr_codec_caps) is 11144 on x86_64
allyesconfig, but x86_64 uses (1<<14), not (1<<13) - x86_64 has more
space in the ioctl payload.

So.  Sound guys: your struct snd_compr_codec_caps is too large for
powerpc ioctls.