[alsa-devel] [BACKPORT 4.4.y 02/25] ALSA: compress: add support for 32bit calls in a 64bit kernel

[Greg KH]

On Tue, Mar 26, 2019 at 08:55:14AM +0100, Arnd Bergmann wrote:
> On Tue, Mar 26, 2019 at 2:23 AM Greg KH <gregkh at linuxfoundation.org> wrote:
> >
> > On Fri, Mar 22, 2019 at 04:43:53PM +0100, Arnd Bergmann wrote:
> > > From: Ravindra Lokhande <rlokhande at nvidia.com>
> > >
> > > Compress offload does not support ioctl calls from a 32bit userspace
> > > in a 64 bit kernel. This patch adds support for ioctls from a 32bit
> > > userspace in a 64bit kernel
> > >
> > > Signed-off-by: Ravindra Lokhande <rlokhande at nvidia.com>
> > > Acked-by: Vinod Koul <vinod.koul at intel.com>
> > > Signed-off-by: Takashi Iwai <tiwai at suse.de>
> > > (cherry picked from commit c10368897e104c008c610915a218f0fe5fa4ec96)
> > > Signed-off-by: Arnd Bergmann <arnd at arndb.de>
> > > ---
> > >  sound/core/compress_offload.c | 13 +++++++++++++
> > >  1 file changed, 13 insertions(+)
> >
> > How is this not a "new feature"?  What bug does this fix?  Has this ever
> > worked in the past?
> 
> It has never worked in the past, but I consider it a bug for the compat layer
> to behave differently from native code. In this case, any 32-bit application
> using the SNDRV_COMPRESS_* ioctls will just fail to do anything on
> a 64-bit kernel at all without the trivial fix that should have been there when
> the driver was originally merged.

Ok, fair enough, now queued up.

greg k-h