patch for dmasound bug

patch for dmasound bug

[Ryan Nielsen]

This restores the rate/byteswap to normal after playing a beep
if you for example stop timidity, make a beep, resume, the sound
will be slower than normal (without this patch).

--- linux/drivers/sound/dmasound.c	1999/02/05 05:45:42	1.41
+++ linux/drivers/sound/dmasound.c	1999/06/02 19:42:08
@@ -3255,6 +3255,11 @@
 	save_flags(flags); cli();
 	if (beep_playing) {
 		st_le16(&beep_dbdma_cmd->command, DBDMA_STOP);
+		out_le32(&awacs_txdma->control, (RUN|PAUSE|FLUSH|WAKE) << 16);
+		out_le32(&awacs->control,
+			 (in_le32(&awacs->control) & ~0x1f00)
+			 | (awacs_rate_index << 8));
+		out_le32(&awacs->byteswap, sound.hard.format != AFMT_S16_BE);
 		beep_playing = 0;
 	}
 	restore_flags(flags);

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Re: patch for dmasound bug

[Alvin Brattli]

OK, this reply comes a bit late, but I didn't try the patch
until now, so here goes:

Ryan Nielsen:
>
>This restores the rate/byteswap to normal after playing a beep
>if you for example stop timidity, make a beep, resume, the sound
>will be slower than normal (without this patch).

Although this patch might do what it was intended for, it has some
unwanted consequences on the PowerBook G3 Series, namely that one gets a
constant, really annoying hiss from the loudspeakers, most notably
during the boot sequence.  Without this patch, the hiss stops after a
system beep (like when you do an "echo ^G" in a shell), but now even
this does not help.  So, if this patch is included in the standard
distribution, I suspect we will hear a lot of complaints from PowerBook
G3 users.

To me, it seems like there is something wrong in the dmasound driver
that causes this hiss; it just doesn't switch off all sound when it's
supposed to.  I don't know enough about the workings of the audio
controller to go bug hunting here myself, so all I can do is just point
out that there is a problem here :(

>--- linux/drivers/sound/dmasound.c	1999/02/05 05:45:42	1.41
>+++ linux/drivers/sound/dmasound.c	1999/06/02 19:42:08
>@@ -3255,6 +3255,11 @@
> 	save_flags(flags); cli();
> 	if (beep_playing) {
> 		st_le16(&beep_dbdma_cmd->command, DBDMA_STOP);
>+		out_le32(&awacs_txdma->control, (RUN|PAUSE|FLUSH|WAKE) << 16);
>+		out_le32(&awacs->control,
>+			 (in_le32(&awacs->control) & ~0x1f00)
>+			 | (awacs_rate_index << 8));
>+		out_le32(&awacs->byteswap, sound.hard.format != AFMT_S16_BE);
> 		beep_playing = 0;
> 	}
> 	restore_flags(flags);



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Re: patch for dmasound bug

[Ryan Nielsen]

Alvin Brattli wrote:
> >This restores the rate/byteswap to normal after playing a beep
> >if you for example stop timidity, make a beep, resume, the sound
> >will be slower than normal (without this patch).
> 
> Although this patch might do what it was intended for, it has some
> unwanted consequences on the PowerBook G3 Series, namely that one gets a
> constant, really annoying hiss from the loudspeakers, most notably
> during the boot sequence.  Without this patch, the hiss stops after a
> system beep (like when you do an "echo ^G" in a shell), but now even
> this does not help.  So, if this patch is included in the standard
> distribution, I suspect we will hear a lot of complaints from PowerBook
> G3 users.

is this better?
--- dmasound.c	1999/02/05 05:45:42	1.41
+++ dmasound.c	1999/06/11 20:04:43
@@ -3255,6 +3255,11 @@
 	save_flags(flags); cli();
 	if (beep_playing) {
 		st_le16(&beep_dbdma_cmd->command, DBDMA_STOP);
+		out_le32(&awacs_txdma->control, (RUN|PAUSE|FLUSH|WAKE) << 16);
+		out_le32(&awacs->control, MASK_IEPC
+			 | (awacs_rate_index << 8) | 0x11
+			 | (awacs_revision < AWACS_BURGUNDY? MASK_IEE: 0));
+		out_le32(&awacs->byteswap, sound.hard.format != AFMT_S16_BE);
 		beep_playing = 0;
 	}
 	restore_flags(flags);

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Re: patch for dmasound bug

[Alvin Brattli]

Ryan Nielsen:
>Alvin Brattli wrote:
>> Although this patch might do what it was intended for, it has some
>> unwanted consequences on the PowerBook G3 Series, namely that one gets a
>> constant, really annoying hiss from the loudspeakers, most notably
>> during the boot sequence.  Without this patch, the hiss stops after a
>> system beep (like when you do an "echo ^G" in a shell), but now even
>> this does not help.  So, if this patch is included in the standard
>> distribution, I suspect we will hear a lot of complaints from PowerBook
>> G3 users.
>
>is this better?
>--- dmasound.c	1999/02/05 05:45:42	1.41
>+++ dmasound.c	1999/06/11 20:04:43
>@@ -3255,6 +3255,11 @@
> 	save_flags(flags); cli();
> 	if (beep_playing) {
> 		st_le16(&beep_dbdma_cmd->command, DBDMA_STOP);
>+		out_le32(&awacs_txdma->control, (RUN|PAUSE|FLUSH|WAKE) << 16);
>+		out_le32(&awacs->control, MASK_IEPC
>+			 | (awacs_rate_index << 8) | 0x11
>+			 | (awacs_revision < AWACS_BURGUNDY? MASK_IEE: 0));
>+		out_le32(&awacs->byteswap, sound.hard.format != AFMT_S16_BE);
> 		beep_playing = 0;
> 	}
> 	restore_flags(flags);

Nope.  The hiss is still there, and won't go away.  If it can be of any
help, the patch below removes the hiss during boot-time when your
patch is not applied.  The patch simply makes a very short beep with
zero volume.  However, after playing certain sounds, the hiss comes
back, and can then be stopped with a system beep (like with "echo ^G" in
a terminal window).


--- linux-2.2.8-orig/drivers/sound/dmasound.c	Fri May 14 22:24:46 1999
+++ linux-2.2.8/drivers/sound/dmasound.c	Sat Jun 12 00:49:44 1999
@@ -4840,6 +4840,7 @@
 	int has_sound = 0;
 #ifdef CONFIG_PPC
 	struct device_node *np;
+	int beep_volume_tmp;
 #endif
 
 #if defined(__mc68000__) || defined(CONFIG_APUS)
@@ -4974,6 +4975,14 @@
 #ifdef MODULE
 	irq_installed = 1;
 #endif
+
+#ifdef CONFIG_PPC
+	/* Remove hiss from PowerBook speakers (very ad hoc) */
+	beep_volume_tmp = beep_volume;
+	beep_volume = 0;
+	awacs_mksound(750, 1);
+	beep_volume = beep_volume_tmp;
+#endif /* CONFIG_PPC */
 
 	printk(KERN_INFO "DMA sound driver installed, using %d buffers of %dk.\n",
 	       numBufs, bufSize);




aLViN
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