Am Montag, 21. November 2011, 05:53:15 schrieb Amit Nagal:
> Thank you for sharing very useful insights .
> Actually in my embedded target , usb audio modules after probe is
> finished , gets unbind .
> when i investigated , the reason is usb reset .
> i am debugging now to know whether this usb reset has come from
> userspace or from some other driver .
Well, that is not productive. The reset may be issued for a perfectly
valid reason and be necessary. It would be far better if the audio driver
handled a reset correctly. Could you test this patch?
Regards
Oliver
>From 4bf7335b3fb573846f8662ed5050fee8502d5da5 Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@xxxxxxxxxx>
Date: Mon, 21 Nov 2011 08:31:23 +0100
Subject: [PATCH] usb-audio: Add reset handler
This is needed on system which share audio interfaces and other
interfaces whose drivers use reset in error handling.
Signed-off-by: Oliver Neukum <oneukum@xxxxxxx>
---
sound/usb/card.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 53 insertions(+), 9 deletions(-)
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 0f6dc0d..f38efc0 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -604,6 +604,21 @@ static void usb_audio_disconnect(struct usb_interface *intf)
usb_get_intfdata(intf));
}
+static void suspend_interfaces(struct snd_usb_audio *chip)
+{
+ struct list_head *p;
+ struct snd_usb_stream *as;
+
+ snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
+ if (!chip->num_suspended_intf++) {
+ list_for_each(p, &chip->pcm_list) {
+ as = list_entry(p, struct snd_usb_stream, list);
+ snd_pcm_suspend_all(as->pcm);
+ }
+ }
+}
+
+
#ifdef CONFIG_PM
int snd_usb_autoresume(struct snd_usb_audio *chip)
@@ -625,21 +640,13 @@ void snd_usb_autosuspend(struct snd_usb_audio *chip)
static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message)
{
struct snd_usb_audio *chip = usb_get_intfdata(intf);
- struct list_head *p;
- struct snd_usb_stream *as;
struct usb_mixer_interface *mixer;
if (chip == (void *)-1L)
return 0;
if (!PMSG_IS_AUTO(message)) {
- snd_power_change_state(chip->card, SNDRV_CTL_POWER_D3hot);
- if (!chip->num_suspended_intf++) {
- list_for_each(p, &chip->pcm_list) {
- as = list_entry(p, struct snd_usb_stream, list);
- snd_pcm_suspend_all(as->pcm);
- }
- }
+ suspend_interfaces(chip);
} else {
/*
* otherwise we keep the rest of the system in the dark
@@ -695,6 +702,41 @@ static struct usb_device_id usb_audio_ids [] = {
{ } /* Terminating entry */
};
+static int usb_audo_pre_reset(struct usb_interface *intf)
+{
+ struct snd_usb_audio *chip = usb_get_intfdata(intf);
+ struct usb_mixer_interface *mixer;
+
+ if (chip == (void *)-1L)
+ return 0;
+
+ list_for_each_entry(mixer, &chip->mixer_list, list)
+ snd_usb_mixer_inactivate(mixer);
+ return 0;
+}
+
+static int usb_audio_post_reset(struct usb_interface *intf)
+{
+ struct snd_usb_audio *chip = usb_get_intfdata(intf);
+ struct usb_mixer_interface *mixer;
+ int err;
+
+ if (chip == (void *)-1L)
+ return 0;
+
+ list_for_each_entry(mixer, &chip->mixer_list, list) {
+ err = snd_usb_mixer_activate(mixer);
+ if (err < 0)
+ goto err_out;
+ }
+ snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);
+
+ return 0;
+
+err_out:
+ return -EIO;
+}
+
MODULE_DEVICE_TABLE (usb, usb_audio_ids);
/*
@@ -707,6 +749,8 @@ static struct usb_driver usb_audio_driver = {
.disconnect = usb_audio_disconnect,
.suspend = usb_audio_suspend,
.resume = usb_audio_resume,
+ .pre_reset = usb_audo_pre_reset,
+ .post_reset = usb_audio_post_reset,
.id_table = usb_audio_ids,
.supports_autosuspend = 1,
};
--
1.7.1
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