Alsa-Devel Archive on lore.kernel.org
 help / color / Atom feed
From: Takashi Iwai <tiwai@suse.de>
To: Keyon Jie <yang.jie@linux.intel.com>
Cc: alsa-devel@alsa-project.org
Subject: Re: [alsa-devel] [PATCH] ALSA: pcm: fix buffer_bytes max constrained by preallocated bytes issue
Date: Thu, 16 Jan 2020 08:15:13 +0100
Message-ID: <s5hd0bjq3cu.wl-tiwai@suse.de> (raw)
In-Reply-To: <20200116045318.5498-1-yang.jie@linux.intel.com>

On Thu, 16 Jan 2020 05:53:18 +0100,
Keyon Jie wrote:
> 
> With today's code, we preallocate DMA buffer for substreams at pcm_new()
> stage, and the substream->buffer_bytes_max and substream->dma_max will
> save as the actually preallocated buffer size and maximum size that the
> dma buffer can be expanded by at hw_params() state, correspondingly.

No, it's other way round: the former, buffer_bytes_max, is the max
size defined by the driver (i.e. passed in snd_pcm_hardware) and the
latter, dma_max, is the max preallocation size (passed to
preallocation helper).

> At pcm_open() stage, the maximum constraint of HW_PARAM_BUFFER_BYTES is
> set to substream->buffer_bytes_max and returned to user space as the max
> interval of the HW_PARAM_BUFFER_BYTES, this will lead to issue that user
> can't choose any buffer-bytes larger than the preallocated buffer size,
> and the buffer reallocation will never happen actually.
> 
> Here change to use substream->dma_max as the maximum constraint of the
> HW_PARAM_BUFFER_BYTES and fix the issue mentioned above.

I don't think the logic in the current code you're changing is wrong.
If there is any, it must be something else.

This might be rather the FIXME code found in
snd_pcm_hw_constraints_complete()?


thanks,

Takashi

> Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
> ---
>  sound/core/pcm_native.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
> index c375c41496f8..326e921006e7 100644
> --- a/sound/core/pcm_native.c
> +++ b/sound/core/pcm_native.c
> @@ -2301,7 +2301,7 @@ static int snd_pcm_hw_rule_buffer_bytes_max(struct snd_pcm_hw_params *params,
>  	struct snd_interval t;
>  	struct snd_pcm_substream *substream = rule->private;
>  	t.min = 0;
> -	t.max = substream->buffer_bytes_max;
> +	t.max = substream->dma_max;
>  	t.openmin = 0;
>  	t.openmax = 0;
>  	t.integer = 1;
> -- 
> 2.20.1
> 
_______________________________________________
Alsa-devel mailing list
Alsa-devel@alsa-project.org
https://mailman.alsa-project.org/mailman/listinfo/alsa-devel

  reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-16  4:53 Keyon Jie
2020-01-16  7:15 ` Takashi Iwai [this message]
2020-01-16  9:50   ` Keyon Jie
2020-01-16 10:27     ` Takashi Iwai
2020-01-16 11:25       ` Keyon Jie
2020-01-16 11:50         ` Takashi Iwai
2020-01-16 14:14           ` Jie, Yang
2020-01-16 15:31             ` Jie, Yang
2020-01-16 16:07               ` Takashi Iwai
2020-01-16 16:39               ` Pierre-Louis Bossart
2020-01-16 17:25                 ` Rajwa, Marcin
2020-01-16 17:40                   ` Pierre-Louis Bossart
2020-01-16 20:37                     ` Takashi Iwai
2020-01-17  5:30                       ` Keyon Jie
2020-01-17  7:57                         ` Takashi Iwai
2020-01-17 10:13                           ` Keyon Jie
2020-01-17 10:30                             ` Takashi Iwai
2020-01-17 10:56                               ` Keyon Jie
2020-01-17 11:15                                 ` Takashi Iwai
2020-01-17  5:37                     ` Keyon Jie
2020-01-17  8:00                       ` Takashi Iwai
2020-01-17 10:43                         ` Keyon Jie
2020-01-17 11:12                           ` Takashi Iwai
2020-01-19  3:52                             ` Keyon Jie
2020-01-19  7:09                               ` Takashi Iwai
2020-01-19  8:11                                 ` Keyon Jie
2020-01-19  9:04                                   ` Takashi Iwai
2020-01-19 10:14                                     ` Keyon Jie
2020-01-19 10:43                                       ` Takashi Iwai
2020-01-20  2:23                                         ` Keyon Jie
2020-01-16 15:45             ` Takashi Iwai

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=s5hd0bjq3cu.wl-tiwai@suse.de \
    --to=tiwai@suse.de \
    --cc=alsa-devel@alsa-project.org \
    --cc=yang.jie@linux.intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Alsa-Devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/alsa-devel/0 alsa-devel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 alsa-devel alsa-devel/ https://lore.kernel.org/alsa-devel \
		alsa-devel@alsa-project.org
	public-inbox-index alsa-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.alsa-project.alsa-devel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git