OSS audio compatibility layer regression - Linux-3.x - unable to register OSS PCM device 0:0

[wallak@free.fr]

I've an issue, when I use the SND_OSSEMUL compatibility layer with the
snd_intel8x0 module. The devices can't be registered. Indeed, theses devices are
registered at the oss_init() stage, and are not available later. A patch to fix
this issue is available below. The patch uses the previous linux behavior.


Best Regards,
Wallak.


#log output
snd_intel8x0 0000:00:1f.5: PCI INT B -> Link[LNKB] -> GSI 10 (level, low) -> IRQ
10
intel8x0_measure_ac97_clock: measured 54899 usecs (2645 samples)
intel8x0: clocking to 48000
unable to register OSS PCM device 0:0
Bridge firewalling registered

#patch fixing this issue: (commit 848669da3a92fa6ab815e0517af3294afb3ea928 adds
this issue)
--- linux-3.1.5-mdf/sound/oss/soundcard.c.orig    2011-12-09 17:57:05.000000000
+0100
+++ linux-3.1.5-mdf/sound/oss/soundcard.c    2011-12-10 15:18:02.000000000 +0100
@@ -526,21 +526,31 @@
 }


+/* These device names follow the official Linux device list,
+ * Documentation/devices.txt.  Let us know if there are other
+ * common names we should support for compatibility.
+ * Only those devices not created by the generic code in sound_core.c are
+ * registered here.
+ */
+static const struct {
+    unsigned short minor;
+    char *name;
+    umode_t mode;
+    int *num;
+} dev_list[] = { /* list of minor devices */
+/* seems to be some confusion here -- this device is not in the device list */
+    {SND_DEV_DSP16,     "dspW",     S_IWUGO | S_IRUSR | S_IRGRP,
+     &num_audiodevs},
+    {SND_DEV_AUDIO,     "audio",     S_IWUGO | S_IRUSR | S_IRGRP,
+     &num_audiodevs},
+};
+
 static int dmabuf;
 static int dmabug;

 module_param(dmabuf, int, 0444);
 module_param(dmabug, int, 0444);

-/* additional minors for compatibility */
-struct oss_minor_dev {
-    unsigned short minor;
-    unsigned int enabled;
-} dev_list[] = {
-    { SND_DEV_DSP16 },
-    { SND_DEV_AUDIO },
-};
-
 static int __init oss_init(void)
 {
     int             err;
@@ -561,12 +571,18 @@
     sound_dmap_flag = (dmabuf > 0 ? 1 : 0);

     for (i = 0; i < ARRAY_SIZE(dev_list); i++) {
-        j = 0;
-        do {
-            unsigned short minor = dev_list[i].minor + j * 0x10;
-            if (!register_sound_special(&oss_sound_fops, minor))
-                dev_list[i].enabled = (1 << j);
-        } while (++j < num_audiodevs);
+        device_create(sound_class, NULL,
+                  MKDEV(SOUND_MAJOR, dev_list[i].minor), NULL,
+                  "%s", dev_list[i].name);
+
+        if (!dev_list[i].num)
+            continue;
+
+        for (j = 1; j < *dev_list[i].num; j++)
+            device_create(sound_class, NULL,
+                      MKDEV(SOUND_MAJOR,
+                        dev_list[i].minor + (j*0x10)),
+                      NULL, "%s%d", dev_list[i].name, j);
     }

     if (sound_nblocks >= MAX_MEM_BLOCKS - 1)
@@ -580,11 +596,11 @@
     int i, j;

     for (i = 0; i < ARRAY_SIZE(dev_list); i++) {
-        j = 0;
-        do {
-            if (dev_list[i].enabled & (1 << j))
-                unregister_sound_special(dev_list[i].minor);
-        } while (++j < num_audiodevs);
+        device_destroy(sound_class, MKDEV(SOUND_MAJOR, dev_list[i].minor));
+        if (!dev_list[i].num)
+            continue;
+        for (j = 1; j < *dev_list[i].num; j++)
+            device_destroy(sound_class, MKDEV(SOUND_MAJOR, dev_list[i].minor +
(j*0x10)));
     }

     unregister_sound_special(1);