-----Original Message----- From: alsa-devel-bounces@alsa-project.org [mailto:alsa-devel-bounces@alsa-project.org] On Behalf Of Vinod Koul Sent: Tuesday, July 19, 2016 12:00 PM To: Lin, Mengdong Cc: alsa-devel@alsa-project.org; Mengdong Lin; tiwai@suse.de; Takashi Sakamoto; broonie@kernel.org; Girdwood, Liam R; Nc, Shreyas Subject: Re: [alsa-devel] [PATCH v2 0/5] topology: Enhance support for private data
On Mon, Jul 18, 2016 at 03:06:24PM +0000, Lin, Mengdong wrote:
-----Original Message----- From: Takashi Sakamoto [mailto:o-takashi@sakamocchi.jp] Sent: Monday, July 18, 2016 11:43 AM
I know all of what you explained. Therefore, You misunderstand about my suggestion.
What I suggested is to drop a support of
SNDRV_CTL_ELEM_ACCESS_USER
flag from current topology implementation in userspace library, because current implementation of ALSA SoC part doesn't support it.
In ALSA SoC part, snd_ctl_new1() is called to add a control element set as a result of parsing binary blob generated by topology
implementation.
In snd_ctl_new1(), SNDRV_CTL_ELEM_ACCESS_USER flag is dropped, in these lines: http://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/tree/sou nd/core/c ontrol.c#n263
Totally, the flag cannot be supported by current implementation of topology in kernel. Thus, in userspace, we should drop this line to prevent users from confusions: http://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=src/topology/ct l.c;h=b94 8ac021ceecc116bc1087075743243e4b14055;hb=HEAD#l44
That's all what I mentioned. If something unclear, please tell it to me.
Yes, you're right. snd_ctl_new1() dropped
SNDRV_CTL_ELEM_ACCESS_USER flag.
I'll remove this from the topology user space tool to avoid confusion.
Oh no, that won't be a good idea.
Hi Vinod,
I think topology will drop support for only one flag "SNDRV_CTL_ELEM_ACCESS_USER". All other access flags are still supported.
Thanks Mengdong
We would like to specify the access for controls from topology. Some controls can be read only and some write only :)
For example, any VU-meter controls should be read-only. Similarly if we have some user data being sent to some modules which can do do all fancy audio detection then these controls should be write-only.
Yes it seems to be broken by this, but we should fix it rather than remove.
-- ~Vinod _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel