Re: [Alsa-devel] Re: devfs unable to handle permission: 2.4.17-pre[4,5] / ALSA-0.9.0beta[9,10]

[Takashi Iwai <tiwai@suse.de>]

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At Thu, 6 Dec 2001 23:09:14 -0700,
Richard Gooch wrote:
> 
> > Also loading the modules gives me:
> > Dec  7 00:31:58 jackson kernel: devfs: devfs_register(unknown): could not append to parent, err: -17
> 
> Two possibilities:
> 
> - the module is trying to register "unknown" twice. The old devfs core
>   was forgiving about this (although it was always a driver bug to
>   attempt to create a duplicate). The new core won't let you do that.
>   Error 17 is EEXIST. Please fix the driver
 
I guess that's a bug (or feature :) in soundcore.

ALSA tries to register the sound devices via register_special(), which
can handle only one card correctly.  All devices on 2nd or 3rd cards
are named as "unknown".

The attached patch will fix this problem.


Takashi

[-- Attachment #2: sound_core.c.dif --]
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--- linux-2.4.10/drivers/sound/sound_core.c	Mon Oct  8 16:33:19 2001
+++ linux-2.4.10.SuSE+LL/drivers/sound/sound_core.c	Mon Oct  8 17:17:49 2001
@@ -231,23 +231,28 @@
  
 int register_sound_special(struct file_operations *fops, int unit)
 {
-	char *name;
+	char *name, name_ext[32];
+	int suffix = 0;
 
-	switch (unit) {
+	switch (unit & 15) {
 	    case 0:
 		name = "mixer";
+		suffix = 1;
 		break;
 	    case 1:
 		name = "sequencer";
 		break;
 	    case 2:
-		name = "midi00";
+		sprintf(name_ext, "midi0%d", unit / SOUND_STEP);
+		name = name_ext;
 		break;
 	    case 3:
 		name = "dsp";
+		suffix = 1;
 		break;
 	    case 4:
 		name = "audio";
+		suffix = 1;
 		break;
 	    case 5:
 		name = "unknown5";
@@ -263,25 +268,34 @@
 		break;
 	    case 9:
 		name = "dmmidi";
+		suffix = 1;
 		break;
 	    case 10:
 		name = "dmfm";
+		suffix = 1;
 		break;
 	    case 11:
 		name = "unknown11";
 		break;
 	    case 12:
 		name = "adsp";
+		suffix = 1;
 		break;
 	    case 13:
 		name = "amidi";
+		suffix = 1;
 		break;
 	    case 14:
 		name = "admmidi";
+		suffix = 1;
 		break;
 	    default:
 		name = "unknown";
 		break;
+	}
+	if (suffix && unit >= SOUND_STEP) {
+	    sprintf(name_ext, "%s%d", name, unit / SOUND_STEP);
+	    name = name_ext;
 	}
 	return sound_insert_unit(&chains[unit&15], fops, -1, unit, unit+1,
 				 name, S_IRUSR | S_IWUSR);