[alsa-devel] [PATCH] snd-usb-us122l v0.4 for US-122L

[Karsten Wiese]

Am Dienstag, 15. April 2008 schrieb Takashi Iwai:
> > > +#endif
> > > +
> > > +#define USB_STREAM_NURBS 4
> > > +struct usb_stream_config {
> > > +	unsigned version;
> > > +	unsigned sample_rate;
> > > +	unsigned period_frames;
> > > +	unsigned frame_size;
> > > +};
> > > 
> > > The codes below here should be hidden to user-space.
> > > If it's exported, then prepare more explicit struct.  For example,
> > > pointers may have different sizes on user-space.
> > 
> > Needed in user-space. Currently only 64Bit userspace works on 64Bit kernel.
> > Also 32bit user-space on 32bit kernel.
> > 32bit user-space on 64bit kernel returns an error to the caller, please see
> > the plugin.
> > IMO 32bit user-space working on 64bit kernel can wait for "INTERFACE_VERSION 2"
> Exporting this kind of particular internal struct to the user-space is
> very dangerous.

Everything exported by that struct can only be mmap()ed "read only".
Please explain why you think its very dangerous.

> This shouldn't be done.
> If a part of the data struct  
> is needed to be accessible via mmap etc, define explicitly the data
> struct instead.

Nearly all of the data struct is used by the user-space plugin.


thanks,
      Karsten