forked from Minki/linux
a91e627e3f
One of the many faults of the QinHeng CH345 USB MIDI interface chip is that it does not handle received SysEx messages correctly -- every second event packet has a wrong code index number, which is the one from the last seen message, instead of 4. For example, the two messages "FE F0 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E F7" result in the following event packets: correct: CH345: 0F FE 00 00 0F FE 00 00 04 F0 01 02 04 F0 01 02 04 03 04 05 0F 03 04 05 04 06 07 08 04 06 07 08 04 09 0A 0B 0F 09 0A 0B 04 0C 0D 0E 04 0C 0D 0E 05 F7 00 00 05 F7 00 00 A class-compliant driver must interpret an event packet with CIN 15 as having a single data byte, so the other two bytes would be ignored. The message received by the host would then be missing two bytes out of six; in this example, "F0 01 02 03 06 07 08 09 0C 0D 0E F7". These corrupted SysEx event packages contain only data bytes, while the CH345 uses event packets with a correct CIN value only for messages with a status byte, so it is possible to distinguish between these two cases by checking for the presence of this status byte. (Other bugs in the CH345's input handling, such as the corruption resulting from running status, cannot be worked around.) Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de> |
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| .. | ||
| aoa | ||
| arm | ||
| atmel | ||
| core | ||
| drivers | ||
| firewire | ||
| hda | ||
| i2c | ||
| isa | ||
| mips | ||
| oss | ||
| parisc | ||
| pci | ||
| pcmcia | ||
| ppc | ||
| sh | ||
| soc | ||
| sparc | ||
| spi | ||
| synth | ||
| usb | ||
| ac97_bus.c | ||
| Kconfig | ||
| last.c | ||
| Makefile | ||
| sound_core.c | ||
| sound_firmware.c | ||