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[36.224.168.33]) by smtp.gmail.com with ESMTPSA id c36-20020a634e24000000b005db034d1514sm3162123pgb.82.2024.03.15.19.38.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Mar 2024 19:38:05 -0700 (PDT) Date: Fri, 15 Mar 2024 22:38:01 -0400 From: Mark Johnston To: Christos Margiolis Cc: status-updates@freebsdfoundation.org, freebsd-multimedia@freebsd.org, jrm@freebsd.org Subject: Re: Re: [Development report #7] Audio Stack Improvements Message-ID: References: List-Id: Multimedia discussions List-Archive: https://lists.freebsd.org/archives/freebsd-multimedia List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-multimedia@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:15169, ipnet:2001:4860:4864::/48, country:US] X-Rspamd-Queue-Id: 4TxQJx2xW4z4r0f On Fri, Mar 15, 2024 at 06:00:16PM +0100, Christos Margiolis wrote: > Hello Mark, > > Mark Johnston wrote: > > > Behavior changes: > > > - Only one /dev/dspX device is exposed, as opposed to the current > > > /dev/dspX.[X]X devices created by the snd_clone mechanism. The > > > user/application now only needs to access the device through /dev/dspX > > > or /dev/dsp and sound(4) will take care of all necessary audio > > > routing. > > > > Does this represent a backward compatibility break? That is, will > > applications need any modification when running on a patched kernel? > > Applications are meant to open an audio device through /dev/dsp (if > hw.snd.basename_clone is enabled), or through /dev/dspX, so the vast > majority of applications should work with no problems. > > Applications that open a device through /dev/dspX.[X]X will break with > this patch. However, opening a device like this is discouraged anyway, > according to the sound(4) man page (see FILES section): To your knowledge, do any popular applications actually do this? A comment in the man page isn't very important if applications end up ignoring it. :) If needed, would it be a lot of work to provide backward compatibility? > [...] > /dev/dsp%d.p%d Playback channel. > /dev/dsp%d.r%d Record channel. > /dev/dsp%d.vp%d Virtual playback channel. > /dev/dsp%d.vr%d Virtual recording channel. > [...] > > The above device nodes are only created on demand through the > dynamic devfs(5) clone handler. Users are strongly discouraged > to access them directly. For specific sound card access, please > instead use /dev/dsp or /dev/dsp%d. > > The patch basically does the same thing -- the output of /dev/sndstat > remains the same -- but without creating these device nodes. > > Christos