From: Pawel Moll Date: Thu, 21 Feb 2013 01:55:50 +0000 (+0000) Subject: ALSA: usb: Fix Processing Unit Descriptor parsers X-Git-Tag: v3.2.40~66 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d3cbb434e8a45001d21bfc3ad31738409e9d517;p=pandora-kernel.git ALSA: usb: Fix Processing Unit Descriptor parsers commit b531f81b0d70ffbe8d70500512483227cc532608 upstream. Commit 99fc86450c439039d2ef88d06b222fd51a779176 "ALSA: usb-mixer: parse descriptors with structs" introduced a set of useful parsers for descriptors. Unfortunately the parses for the Processing Unit Descriptor came with a very subtle bug... Functions uac_processing_unit_iProcessing() and uac_processing_unit_specific() were indexing the baSourceID array forgetting the fields before the iProcessing and process-specific descriptors. The problem was observed with Sound Blaster Extigy mixer, where nNrModes in Up/Down-mix Processing Unit Descriptor was accessed at offset 10 of the descriptor (value 0) instead of offset 15 (value 7). In result the resulting control had interesting limit values: Simple mixer control 'Channel Routing Mode Select',0 Capabilities: volume volume-joined penum Playback channels: Mono Capture channels: Mono Limits: 0 - -1 Mono: -1 [100%] Fixed by starting from the bmControls, which was calculated correctly, instead of baSourceID. Now the mentioned control is fine: Simple mixer control 'Channel Routing Mode Select',0 Capabilities: volume volume-joined penum Playback channels: Mono Capture channels: Mono Limits: 0 - 6 Mono: 0 [0%] Signed-off-by: Pawel Moll Signed-off-by: Takashi Iwai [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed