From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: Major problem with the current alsa mixer. Date: Fri, 12 Sep 2003 10:57:12 +0200 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: References: <3F610FE4.2040009@superbug.demon.co.uk> Mime-Version: 1.0 (generated by SEMI 1.14.5 - "Awara-Onsen") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Jaroslav Kysela Cc: James Courtier-Dutton , alsa-devel List-Id: alsa-devel@alsa-project.org At Fri, 12 Sep 2003 09:23:13 +0200 (CEST), Jaroslav wrote: > > On Fri, 12 Sep 2003, James Courtier-Dutton wrote: > > > There is a MAJOR problem with the current alsa mixer. > > How do I set a mixer volume to the 0 db point. I.E. no attenuation, and > > no gain. > > Currently, we might have a value from 0 to 100%. Percent of what? > > Percent of the volume range. > > > What this value means varies depending on the sound card hardware being > > used. > > I think that this should all be changed to signed values, with a max and > > a min setting. With a value of 0 being equivalent to no-gain, > > no-attenuation. Each alsa-driver would then convert this signed value > > into a value actually written to the hardware register via a lookup table. > > Things are not as easy as you like. Using the signed notation for the > volume representation does not sound bad, but on the other side, it's > great to have zero as minimum value as well. > > I have plans to extend the mixer interface to pass (and handle) the dB > resolution. But it will be done completely in the user space. The alsa-lib > will analyze information from the driver (hardware components) and then it > will use a predefined expressions for these transformations. I think that > we should not polute the kernel space with these "additional" things. agreed. it's a user-space thing. but some additional information like min/max dB would be needed, too? Takashi ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf