Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756716Ab3EJO0r (ORCPT ); Fri, 10 May 2013 10:26:47 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:57379 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756149Ab3EJO0W (ORCPT ); Fri, 10 May 2013 10:26:22 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Takashi Iwai" , "Clemens Ladisch" Date: Fri, 10 May 2013 14:39:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [029/118] ALSA: usb-audio: disable autopm for MIDI devices In-Reply-To: X-SA-Exim-Connect-IP: 2001:470:1f08:1539:d51a:8785:aa0a:cebe X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3169 Lines: 93 [Re-sending without the address-less name in Cc.] 3.2.45-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Clemens Ladisch commit cbc200bca4b51a8e2406d4b654d978f8503d430b upstream. Commit 88a8516a2128 (ALSA: usbaudio: implement USB autosuspend) introduced autopm for all USB audio/MIDI devices. However, many MIDI devices, such as synthesizers, do not merely transmit MIDI messages but use their MIDI inputs to control other functions. With autopm, these devices would get powered down as soon as the last MIDI port device is closed on the host. Even some plain MIDI interfaces could get broken: they automatically send Active Sensing messages while powered up, but as soon as these messages cease, the receiving device would interpret this as an accidental disconnection. Commit f5f165418cab (ALSA: usb-audio: Fix missing autopm for MIDI input) introduced another regression: some devices (e.g. the Roland GAIA SH-01) are self-powered but do a reset whenever the USB interface's power state changes. To work around all this, just disable autopm for all USB MIDI devices. Reported-by: Laurens Holst Signed-off-by: Clemens Ladisch Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings --- sound/usb/midi.c | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -126,7 +126,6 @@ struct snd_usb_midi { struct snd_usb_midi_in_endpoint *in; } endpoints[MIDI_MAX_ENDPOINTS]; unsigned long input_triggered; - bool autopm_reference; unsigned int opened[2]; unsigned char disconnected; unsigned char input_running; @@ -1040,7 +1039,6 @@ static int substream_open(struct snd_raw { struct snd_usb_midi* umidi = substream->rmidi->private_data; struct snd_kcontrol *ctl; - int err; down_read(&umidi->disc_rwsem); if (umidi->disconnected) { @@ -1051,13 +1049,6 @@ static int substream_open(struct snd_raw mutex_lock(&umidi->mutex); if (open) { if (!umidi->opened[0] && !umidi->opened[1]) { - err = usb_autopm_get_interface(umidi->iface); - umidi->autopm_reference = err >= 0; - if (err < 0 && err != -EACCES) { - mutex_unlock(&umidi->mutex); - up_read(&umidi->disc_rwsem); - return -EIO; - } if (umidi->roland_load_ctl) { ctl = umidi->roland_load_ctl; ctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_INACTIVE; @@ -1080,8 +1071,6 @@ static int substream_open(struct snd_raw snd_ctl_notify(umidi->card, SNDRV_CTL_EVENT_MASK_INFO, &ctl->id); } - if (umidi->autopm_reference) - usb_autopm_put_interface(umidi->iface); } } mutex_unlock(&umidi->mutex); @@ -2256,6 +2245,8 @@ int snd_usbmidi_create(struct snd_card * return err; } + usb_autopm_get_interface_no_resume(umidi->iface); + list_add_tail(&umidi->list, midi_list); return 0; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/