From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753760Ab3BUNUW (ORCPT ); Thu, 21 Feb 2013 08:20:22 -0500 Received: from cantor2.suse.de ([195.135.220.15]:40512 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752901Ab3BUNUU (ORCPT ); Thu, 21 Feb 2013 08:20:20 -0500 Date: Thu, 21 Feb 2013 14:20:19 +0100 Message-ID: From: Takashi Iwai To: Daniel Mack Cc: Pawel Moll , Jaroslav Kysela , Daniel Mack , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ALSA: usb: Fix Processing Unit Descriptor parsers In-Reply-To: <51260EA8.20402@gmail.com> References: <1361411750-30056-1-git-send-email-mail@pawelmoll.com> <51260EA8.20402@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.2 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At Thu, 21 Feb 2013 13:10:16 +0100, Daniel Mack wrote: > > On 21.02.2013 10:03, Takashi Iwai wrote: > > At Thu, 21 Feb 2013 01:55:50 +0000, > > Pawel Moll wrote: > >> > >> 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 > >> --- > >> include/uapi/linux/usb/audio.h | 6 ++++-- > >> 1 file changed, 4 insertions(+), 2 deletions(-) > >> > >> diff --git a/include/uapi/linux/usb/audio.h b/include/uapi/linux/usb/audio.h > >> index ac90037..d2314be 100644 > >> --- a/include/uapi/linux/usb/audio.h > >> +++ b/include/uapi/linux/usb/audio.h > >> @@ -384,14 +384,16 @@ static inline __u8 uac_processing_unit_iProcessing(struct uac_processing_unit_de > >> int protocol) > >> { > >> __u8 control_size = uac_processing_unit_bControlSize(desc, protocol); > >> - return desc->baSourceID[desc->bNrInPins + control_size]; > >> + return *(uac_processing_unit_bmControls(desc, protocol) > >> + + control_size); > >> } > >> > >> static inline __u8 *uac_processing_unit_specific(struct uac_processing_unit_descriptor *desc, > >> int protocol) > >> { > >> __u8 control_size = uac_processing_unit_bControlSize(desc, protocol); > >> - return &desc->baSourceID[desc->bNrInPins + control_size + 1]; > >> + return uac_processing_unit_bmControls(desc, protocol) > >> + + control_size + 1; > >> } > > > > Looks good to me. > > > > An alternative would be to change uac_processing_unit_bControlSize() > > to correct the header size, but I don't think it's good, as > > bControlSize fields in other units show the value including the header > > size. > > > > Daniel, what do you think? > > Looks good to me too. and this should be marked for stable of course. > > Thanks for fixing this, Pawell! OK, applied now. Thanks. Takashi