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authorClemens Ladisch <clemens@ladisch.de>2015-11-15 22:38:29 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-12-09 13:43:00 -0500
commitd1f4bf8d843595e0ab08428cbcb063e4d5cba2ef (patch)
treec5a826691862680994288b62b0d2369d03b637f7
parent840ff74ffc06b2a1792226bd0234708cbab60eb7 (diff)
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ALSA: usb-audio: prevent CH345 multiport output SysEx corruption
commit 1ca8b201309d842642f221db7f02f71c0af5be2d upstream. The CH345 USB MIDI chip has two output ports. However, they are multiplexed through one pin, and the number of ports cannot be reduced even for hardware that implements only one connector, so for those devices, data sent to either port ends up on the same hardware output. This becomes a problem when both ports are used at the same time, as longer MIDI commands (such as SysEx messages) are likely to be interrupted by messages from the other port, and thus to get lost. It would not be possible for the driver to detect how many ports the device actually has, except that in practice, _all_ devices built with the CH345 have only one port. So we can just ignore the device's descriptors, and hardcode one output port. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--sound/usb/midi.c3
-rw-r--r--sound/usb/quirks-table.h11
-rw-r--r--sound/usb/quirks.c1
-rw-r--r--sound/usb/usbaudio.h1
4 files changed, 16 insertions, 0 deletions
diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index fa9028e79dba..966051f530bd 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -2291,6 +2291,9 @@ int snd_usbmidi_create(struct snd_card *card,
err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
break;
+ case QUIRK_MIDI_CH345:
+ err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+ break;
default:
snd_printd(KERN_ERR "invalid quirk type %d\n", quirk->type);
err = -ENXIO;
diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 7c24088bcaa4..c600d4277974 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -2875,6 +2875,17 @@ YAMAHA_DEVICE(0x7010, "UB99"),
.idProduct = 0x1020,
},
+/* QinHeng devices */
+{
+ USB_DEVICE(0x1a86, 0x752d),
+ .driver_info = (unsigned long) &(const struct snd_usb_audio_quirk) {
+ .vendor_name = "QinHeng",
+ .product_name = "CH345",
+ .ifnum = 1,
+ .type = QUIRK_MIDI_CH345
+ }
+},
+
/* KeithMcMillen Stringport */
{
USB_DEVICE(0x1f38, 0x0001),
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 827d40441ec7..901f87dea827 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -526,6 +526,7 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
[QUIRK_MIDI_CME] = create_any_midi_quirk,
[QUIRK_MIDI_AKAI] = create_any_midi_quirk,
[QUIRK_MIDI_FTDI] = create_any_midi_quirk,
+ [QUIRK_MIDI_CH345] = create_any_midi_quirk,
[QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_audio_quirk,
[QUIRK_AUDIO_FIXED_ENDPOINT] = create_fixed_stream_quirk,
[QUIRK_AUDIO_EDIROL_UAXX] = create_uaxx_quirk,
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 5d2fe0530745..e5b2c30a8e90 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -84,6 +84,7 @@ enum quirk_type {
QUIRK_MIDI_AKAI,
QUIRK_MIDI_US122L,
QUIRK_MIDI_FTDI,
+ QUIRK_MIDI_CH345,
QUIRK_AUDIO_STANDARD_INTERFACE,
QUIRK_AUDIO_FIXED_ENDPOINT,
QUIRK_AUDIO_EDIROL_UAXX,