LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Takashi Iwai <tiwai@suse.de>
To: David Miller <davem@davemloft.net>
Cc: bzolnier@gmail.com, sven.koehler@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: sound skipping regression introduced in 2.6.30-rc8
Date: Mon, 15 Jun 2009 11:58:13 +0200
Message-ID: <s5htz2hes3u.wl%tiwai@suse.de> (raw)
In-Reply-To: <s5hy6rtesjo.wl%tiwai@suse.de>

At Mon, 15 Jun 2009 11:48:43 +0200,
I wrote:
> 
> At Mon, 15 Jun 2009 02:25:47 -0700 (PDT),
> David Miller wrote:
> > 
> > From: Takashi Iwai <tiwai@suse.de>
> > Date: Mon, 15 Jun 2009 10:39:50 +0200
> > 
> > > If that patch also doesn't work, we need to track the position update
> > > sequence in more details.
> > > The patch below will dump the each position update (CAUTION: it can be
> > > long logs!).  Please apply it instead of the previous one, run with
> > > xrun_debug=5 on 2.6.31 (or xrun_debug=1 on 2.6.30), and give the
> > > outputs around a skip occurs.
> > 
> > The patch doesn't work.
> > 
> > I put up a debugging log at:
> > 
> > 	http://vger.kernel.org/~davem/asound.log
> > 
> > there is a "PCM: hw_ptr skipping! ..." message near the end.
> 
> Thanks!  I see the problem now.  It's a race in the update of the
> current buffer position.  The counter was reset to the full fragment
> size, but its index still points the previous position.  So, the
> driver was confused and put the position back.
> 
> The below is a revised patch.  It has an additional sanity check.
> Please give it a try.

Damn, that was buggy again.  The fixed version is below.


Takashi

---
diff --git a/sound/pci/intel8x0.c b/sound/pci/intel8x0.c
index 173bebf..8aa5687 100644
--- a/sound/pci/intel8x0.c
+++ b/sound/pci/intel8x0.c
@@ -356,8 +356,6 @@ struct ichdev {
         unsigned int position;
 	unsigned int pos_shift;
 	unsigned int last_pos;
-	unsigned long last_pos_jiffies;
-	unsigned int jiffy_to_bytes;
         int frags;
         int lvi;
         int lvi_frag;
@@ -844,7 +842,6 @@ static int snd_intel8x0_pcm_trigger(struct snd_pcm_substream *substream, int cmd
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 		val = ICH_IOCE | ICH_STARTBM;
 		ichdev->last_pos = ichdev->position;
-		ichdev->last_pos_jiffies = jiffies;
 		break;
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 		ichdev->suspended = 1;
@@ -1048,7 +1045,6 @@ static int snd_intel8x0_pcm_prepare(struct snd_pcm_substream *substream)
 			ichdev->pos_shift = (runtime->sample_bits > 16) ? 2 : 1;
 	}
 	snd_intel8x0_setup_periods(chip, ichdev);
-	ichdev->jiffy_to_bytes = (runtime->rate * 4 * ichdev->pos_shift) / HZ;
 	return 0;
 }
 
@@ -1073,19 +1069,23 @@ static snd_pcm_uframes_t snd_intel8x0_pcm_pointer(struct snd_pcm_substream *subs
 		    ptr1 == igetword(chip, ichdev->reg_offset + ichdev->roff_picb))
 			break;
 	} while (timeout--);
+	ptr = ichdev->last_pos;
 	if (ptr1 != 0) {
 		ptr1 <<= ichdev->pos_shift;
 		ptr = ichdev->fragsize1 - ptr1;
 		ptr += position;
-		ichdev->last_pos = ptr;
-		ichdev->last_pos_jiffies = jiffies;
-	} else {
-		ptr1 = jiffies - ichdev->last_pos_jiffies;
-		if (ptr1)
-			ptr1 -= 1;
-		ptr = ichdev->last_pos + ptr1 * ichdev->jiffy_to_bytes;
-		ptr %= ichdev->size;
+		if (ptr < ichdev->last_pos) {
+			unsigned int pos_base, last_base;
+			pos_base = position / ichdev->fragsize1;
+			last_base = ichdev->last_pos / ichdev->fragsize1;
+			/* another sanity check; ptr1 can go back to full
+			 * before the base position is updated
+			 */
+			if (pos_base == last_base)
+				ptr = ichdev->last_pos;
+		}
 	}
+	ichdev->last_pos = ptr;
 	spin_unlock(&chip->reg_lock);
 	if (ptr >= ichdev->size)
 		return 0;

  reply index

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-10 18:28 David Miller
2009-06-10 19:37 ` Takashi Iwai
2009-06-11 11:28   ` David Miller
2009-06-11 12:02   ` David Miller
2009-06-11 13:32     ` Bartlomiej Zolnierkiewicz
2009-06-11 13:56       ` Takashi Iwai
2009-06-11 14:14         ` Bartlomiej Zolnierkiewicz
2009-06-11 14:23           ` Takashi Iwai
2009-06-11 15:40             ` Bartlomiej Zolnierkiewicz
2009-06-11 16:07               ` Takashi Iwai
2009-06-11 17:36                 ` Bartlomiej Zolnierkiewicz
2009-06-11 14:02     ` Takashi Iwai
2009-06-10 19:37 ` Sven Köhler
2009-06-11  0:58   ` Takashi Iwai
2009-06-11  6:47     ` Sven Köhler
2009-06-11  8:18       ` Takashi Iwai
2009-06-11 21:38         ` Sven Köhler
2009-06-12  1:52           ` Takashi Iwai
2009-06-12 11:44             ` Bartlomiej Zolnierkiewicz
2009-06-15  8:30               ` Takashi Iwai
2009-06-15  8:39                 ` Takashi Iwai
2009-06-15  9:25                   ` David Miller
2009-06-15  9:48                     ` Takashi Iwai
2009-06-15  9:58                       ` Takashi Iwai [this message]
2009-06-15 10:11                         ` David Miller
2009-06-15 10:26                           ` Takashi Iwai
2009-06-15 18:25                         ` Sven Köhler
2009-06-15 19:15                           ` Bartlomiej Zolnierkiewicz
2009-06-15 10:09                       ` David Miller
2009-06-15  9:18                 ` David Miller

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=s5htz2hes3u.wl%tiwai@suse.de \
    --to=tiwai@suse.de \
    --cc=bzolnier@gmail.com \
    --cc=davem@davemloft.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sven.koehler@gmail.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

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

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

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


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