Re: [PATCH - JACK PCM plugin] jack: Use boundary as hw_ptr wrap around

From: Takashi Iwai <tiwai@suse.de>
To: twischer@de.adit-jv.com
Cc: alsa-devel@alsa-project.org
Subject: Re: [PATCH - JACK PCM plugin] jack: Use boundary as hw_ptr	wrap around
Date: Sat, 24 Feb 2018 11:43:36 +0100	[thread overview]
Message-ID: <s5hk1v2zmzr.wl-tiwai@suse.de> (raw)
In-Reply-To: <1519395488-6735-1-git-send-email-twischer@de.adit-jv.com>

On Fri, 23 Feb 2018 15:18:08 +0100,
<twischer@de.adit-jv.com> wrote:
> 
> From: Timo Wischer <twischer@de.adit-jv.com>
> 
> instead of using buffer_size as wrap around.
> 
> This is required to detect Xruns.
> 
> It is also required to allow the JACK thread
> to processes the whole ALSA audio buffer at once
> without calling snd_pcm_avail_update() in between.
> 
> For example when the hw_ptr will be updated with
> hw_ptr += buffer_size
> and it is using the buffer_size as wrap around
> hw_ptr %= buffer_size
> would result in the same value as before the add operation.
> 
> Due to that the user application would not recognize
> that the complete audio buffer was copied.
> 
> Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
> 
> ---
> 
> Here the updated version which only returns
> hw_ptr >= buffer_size if supported
> by the ALSA library on compile time

Thanks, applied now together with your alsa-lib patch.

Takashi