diff options
| author | Clemens Ladisch <clemens@ladisch.de> | 2015-11-15 22:38:29 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-12-09 14:34:42 -0500 |
| commit | a90b6640f8dfea2ab42c9cce3fc1d45bb169ca65 (patch) | |
| tree | f91a94f48b44235e1fb9faec5d127b0cf7d9faa4 | |
| parent | da3e8b3f94a8f2c511dba4192ea994b6abcdaa59 (diff) | |
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.c | 3 | ||||
| -rw-r--r-- | sound/usb/quirks-table.h | 11 | ||||
| -rw-r--r-- | sound/usb/quirks.c | 1 | ||||
| -rw-r--r-- | sound/usb/usbaudio.h | 1 |
4 files changed, 16 insertions, 0 deletions
diff --git a/sound/usb/midi.c b/sound/usb/midi.c index 4bed82c70256..5010aadb2534 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -2376,6 +2376,9 @@ 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: dev_err(&umidi->dev->dev, "invalid quirk type %d\n", quirk->type); diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h index e4756651a52c..ecc2a4ea014d 100644 --- a/sound/usb/quirks-table.h +++ b/sound/usb/quirks-table.h @@ -2820,6 +2820,17 @@ 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 528fa6e48293..eef9b8e4b949 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -535,6 +535,7 @@ 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 33a176437e2e..4b4327b45606 100644 --- a/sound/usb/usbaudio.h +++ b/sound/usb/usbaudio.h @@ -94,6 +94,7 @@ 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, |