Date: Sun, 17 Aug 2014 17:24:56 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-usb@FreeBSD.org Subject: [Bug 192755] New: snd_uaudio incorrect handling of version 1 audio format type descriptor Message-ID: <bug-192755-17@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=192755 Bug ID: 192755 Summary: snd_uaudio incorrect handling of version 1 audio format type descriptor Product: Base System Version: 10.0-STABLE Hardware: amd64 OS: Any Status: Needs Triage Severity: Affects Only Me Priority: --- Component: usb Assignee: freebsd-usb@FreeBSD.org Reporter: juanmasf2@ono.com For USB audio 1.0 formats the code in uaudio.c uses the value of bBitResolution from the descriptor directly to choose and internal audio format from the array uaudio10_formats. It should use the value from bSubFrameSize instead. It is clearly specified in the official USB document for audio data formats, page 9 under the section "2.2.2 Audio Subframe" that the endpoint must be handled using bSubFramSize*8 bits per sample from which the device will take the number of bits it actually uses. In my particular case I own a device reporting bBitResolution of 24 and bSubFrameSize of 4. An unpatched driver will be sending 3-byte subframes to the endpoint resulting in pure noise :) For USB 2.0 formats the code already does some conversion to avoid this same problem, using the equivalent bSubslotSize in the function uaudio_chan_fill_info_sub: /* Map 4-byte aligned 24-bit samples into 32-bit */ if (bBitResolution == 24 && bSubslotSize == 4) bBitResolution = 32; if (bBitResolution != (bSubslotSize * 8)) { DPRINTF("Invalid bSubslotSize\n"); goto next_ep; } -- You are receiving this mail because: You are the assignee for the bug.
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