From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Courtier-Dutton Subject: Bug in ALSA OSS mixer emulation. Volume++ does not work. Date: Wed, 03 Dec 2003 03:27:44 +0000 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <3FCD5830.2000702@superbug.demon.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: alsa-devel List-Id: alsa-devel@alsa-project.org Hi, The alsa keeps state of all mixer levels in alsa's internal format which has min,max info. So, for example if alsa has 0-31 levels, converting that to the OSS 0-100 range is easy with a simple calculation, but if an OSS app just does Volume++, the change will be lost in the conversion from OSS to ALSA to actually set the state. So, to work the way it should, OSS will have to cache all mixer state in OSS format, thus requiring 2 state tables. E.g. OSS Volume(0-100) ALSA Volume(0-31) OSS = ALSA * 100/31; 0 0 1 0 2 0 3 1 4 1 etc. So, if OSS Volume is 2, and the OSS application does Volume++, the OSS volume will be set to 3. but if OSS Volume is 3, and the OSS application does Volume++, the OSS volume will stay at 3! Cheers James ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. Does SourceForge.net help you be more productive? Does it help you create better code? SHARE THE LOVE, and help us help YOU! Click Here: http://sourceforge.net/donate/