On Mon, Nov 21, 2011 at 1:07 PM, Oliver Neukum <oneukum@xxxxxxx> wrote:
> 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
>
>
Ok , i checked above patch and with this audio modules donot get unbind now .
i am using usb device ( ipod ) as capture only device for usb audio streaming .
will the above patch also cease i/o related to usb capture in pre
reset functionality
and restore it in post reset ?
Also , i have not test the case with the above patch when usb audio
streaming (capture ) is in progress
and a usb reset is issued .
Thanx & Regards
Amit Nagal
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
