Commit 4ca231b2 authored Apr 29, 2013 by Eldad Zack Committed by Takashi Iwai Apr 30, 2013

ALSA: usb-audio: caiaq: fix endianness bug in snd_usb_caiaq_maschine_dispatch



Current code does this:

  be16_to_cpu(buf[i * 2] << 8 | buf[(i * 2) + 1])

Which is effectively (neglecting the index):

  be16_to_cpu(be16_to_cpu(*((u16 *) buf)))

This means the int16 in the buffer is not converted at all.

Daniel Mack confirmed that the driver works on little endian
CPUs, leading to the conclusion that the device-side structure
is actually little endian.
This changes the code to use le16_to_cpu().

Caught by sparse.

Acked-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent 167d0a11

sound/usb/caiaq/input.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -488,13 +488,13 @@ static void snd_usb_caiaq_maschine_dispatch(struct snd_usb_caiaqdev *cdev,
		unsigned int len)
		{
		unsigned int i, pad_id;
		uint16_t pressure;
		__le16 pressure = (__le16 ) buf;

		for (i = 0; i < MASCHINE_PADS; i++) {
		pressure = be16_to_cpu(buf[i * 2] << 8 \| buf[(i * 2) + 1]);
		pad_id = pressure >> 12;

		input_report_abs(cdev->input_dev, MASCHINE_PAD(pad_id), pressure & 0xfff);
		pad_id = le16_to_cpu(*pressure) >> 12;
		input_report_abs(cdev->input_dev, MASCHINE_PAD(pad_id),
		le16_to_cpu(*pressure) & 0xfff);
		pressure++;
		}

		input_sync(cdev->input_dev);

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