From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 31B7C80630 for ; Mon, 29 Apr 2024 15:00:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714402842; cv=none; b=GdbHt9SA8G2EBXxSDb2xViOurCoJmUIb8HhLcD45WR1ZgtQ5hmx7ith3acZ9zMmk0oDdhcUSG8KEDHtSu/mL8YOba55u0+upJtUp7dUHcKoI1+gIIM4CQJnbLPcMtoDscvx3+Gp90gRxT1oKIve8sNSsaTs+0RIC+mwgn/MOYSg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714402842; c=relaxed/simple; bh=1EwieA7QUF9rLJWyLDX+qUl7U2/uRBK3RtLbBgX3Hww=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=e80rmFDpPwelUaIo+scuwM/oefPCz9KQgxnAS5F+Y3XLSD+r16muhqRrbX6Psl/m2hynHy/dHyE0uXiglSh8Qni/IefdDR00v0oHrJ3oZmD0YNyGQskPnh2UH1g+7nU35GeYJI/t2bxqUKtuDM88VoU1OFsOsvPzrZDELjVQzH4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Vy+Ua44h; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Vy+Ua44h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F4025C113CD; Mon, 29 Apr 2024 15:00:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714402842; bh=1EwieA7QUF9rLJWyLDX+qUl7U2/uRBK3RtLbBgX3Hww=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Vy+Ua44hajpgT2+BhYXGsME5V8NCe8v21/S768xNPsTQnz2zGWqtiIGDYg0cem1IQ 2kpWL9AIxmhHYNFt7U7OHCFKPdGhP1npPJgRH0zsZG6q9oaBsTHX1wwB72vpN6W2pV w6a8zfnUHIEPeQpTDBZslcLWfx4q7rFU6Bn7Er53CI1Iko6CsACOHrjUy0KQ7GAib+ s753iW4wcAVzxKby6OaK3OraQdvZBcQN0Rng1G64S4XQQ+yCol/sejf7DOa07FQROy MdqXkWq+8b54M+1rEYed0DhZ+DYt2Km/dWs7WTNWvxe/Kwusp4eKT3cdGZ5VQxO3qN xL6KBfcREkVaQ== Received: from johan by xi.lan with local (Exim 4.97.1) (envelope-from ) id 1s1SUj-000000005LT-3cUe; Mon, 29 Apr 2024 17:00:41 +0200 Date: Mon, 29 Apr 2024 17:00:41 +0200 From: Johan Hovold To: Srinivas Kandagatla Cc: broonie@kernel.org, perex@perex.cz, tiwai@suse.com, lgirdwood@gmail.com, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, Bjorn Andersson Subject: Re: [PATCH v2 0/4] ASoC: qcom: display port changes Message-ID: References: <20240422134354.89291-1-srinivas.kandagatla@linaro.org> <92b02fd3-5eba-42a7-a166-21b14724b10c@linaro.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 23, 2024 at 04:59:56PM +0100, Srinivas Kandagatla wrote: > On 23/04/2024 15:58, Johan Hovold wrote: > >> It is absolutely possible to run all the streams in parallel from the > >> Audio hardware and DSP point of view. > >> > >> One thing to note is, On Qualcomm DP IP, we can not read/write registers > >> if the DP port is not connected, which means that we can not send data > >> in such cases. > >> > >> This makes it challenging to work with sound-servers like pipewire or > >> pulseaudio as they tend to send silence data at very early stages in the > >> full system boot up, ignoring state of the Jack events. > > This bit sounds like it can and should be worked around by the driver to > > avoid hard-coding policy which would prevent use cases such as the ones > > mentioned above. > This is not simple as you say. We have to fit these into a proper DPCM. > Either we have a dummy Backend connected for each of these pcm > sub-devices when DP port is not connected and then switch back to DP > when its connected. I don't know how best to implement it, but we shouldn't necessarily let that determine the user experience. > Or somehow find a way to not let the pipewire talk to devices which are > not connected. Yes, perhaps it requires a change in user space. But it seems the kernel should be able to fake whatever probing user space currently does to determine if the there is a DP jack (even when there is nothing connected). Johan