[pulseaudio-discuss] [RFC PATCH] bluetooth: Fix assertion failure (decoded == a2dp->frame_length)

[Tanu Kaskinen]

On Wed, 2012-10-10 at 09:17 +0200, David Henningsson wrote:
> According to the patch author, Karl Hegbloom:
> "The assertion is incorrectly testing for '==' when logically it
> should test for '<='."
> 
> BugLink: https://bugs.launchpad.net/bugs/689915
> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
> ---
> 
> This is a patch I found attached to a bug in Ubuntu. I don't know
> much about bluetooth, and the error was reported against something
> around 0.9.22. But I'm sending it here, hoping that one of our
> bluetooth people can review and say whether this is correct or not.
> 
>  src/modules/bluetooth/module-bluetooth-device.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/src/modules/bluetooth/module-bluetooth-device.c b/src/modules/bluetooth/module-bluetooth-device.c
> index e3ec6ae..06c783d 100644
> --- a/src/modules/bluetooth/module-bluetooth-device.c
> +++ b/src/modules/bluetooth/module-bluetooth-device.c
> @@ -999,9 +999,9 @@ static int a2dp_process_push(struct userdata *u) {
>              a2dp->frame_length = sbc_get_frame_length(&a2dp->sbc);
>  
>              pa_assert_fp((size_t) decoded <= to_decode);
> -            pa_assert_fp((size_t) decoded == a2dp->frame_length);
> +            pa_assert_fp((size_t) decoded <= a2dp->frame_length);
>  
> -            pa_assert_fp((size_t) written == a2dp->codesize);
> +            pa_assert_fp((size_t) written <= a2dp->codesize);
>  
>              p = (const uint8_t*) p + decoded;
>              to_decode -= decoded;

I'm no SBC expert either, but I had a look at sbc_decode()
implementation, and to me it looks like at least "decoded ==
a2dp->frame_length" should hold. Extrapolating from that, "written ==
a2dp->codesize" probably should hold too. And it makes sense:
sbc_decode() is supposed to decode one frame, and I think one frame will
always have encoded size of a2dp->frame_length and decoded size of
a2dp->codesize.

-- 
Tanu