From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754019AbdJIIhB (ORCPT ); Mon, 9 Oct 2017 04:37:01 -0400 Received: from heliosphere.sirena.org.uk ([172.104.155.198]:59912 "EHLO heliosphere.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751598AbdJIIg7 (ORCPT ); Mon, 9 Oct 2017 04:36:59 -0400 Date: Mon, 9 Oct 2017 09:36:56 +0100 From: Mark Brown To: "Levin, Alexander (Sasha Levin)" Cc: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Matt Ranostay , Liam Breck Subject: Re: [PATCH review for 4.9 39/50] ASoC: omap-mcbsp: Add PM QoS support for McBSP to prevent glitches Message-ID: <20171009083656.u2fii7bbae5fsda4@sirena.co.uk> References: <20171007223636.24797-1-alexander.levin@verizon.com> <20171007223636.24797-39-alexander.levin@verizon.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="35zwmrjw4ehyged7" Content-Disposition: inline In-Reply-To: <20171007223636.24797-39-alexander.levin@verizon.com> X-Cookie: Use a pun, go to jail. User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --35zwmrjw4ehyged7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Oct 07, 2017 at 10:36:55PM +0000, Levin, Alexander (Sasha Levin) wr= ote: > From: Matt Ranostay >=20 > [ Upstream commit 9834ffd1ecc3a401d0ce64c2d4235a726da6d4f9 ] >=20 > We can get audio errors if hitting deeper idle states on omaps: >=20 > [alsa.c:230] error: Fatal problem with alsa output, error -5. > [audio.c:614] error: Error in writing audio (Input/output error?)! >=20 > This seems to happen with off mode idle enabled as power for the > whole SoC may get cut off between filling the McBSP fifo using DMA. > While active DMA blocks deeper idle states in hardware, McBSP > activity does not seem to do so. This seems rather invasive and fancy for stable material - people might want it in production but they may also not have enough power management enabled to be seeing the problems it fixes. --35zwmrjw4ehyged7 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAlnbNScACgkQJNaLcl1U h9BjuAf+N9vlqOWMyTGhZwsJQlKXEDsnPPo6qTTLCjHde0nK/EpSYmsWazo6eajh 0NmfQVKd/qj24kpAv80yNi5mbiEhd+0peixj2hxZOnHw6i9WCi8WOQkNvgEWuvNe L0DypCDwNmddTNTxmZxCJbRb2vgURGRrJtPaSjkxDZe/bipNapJHEs6UfLx1seMb llHeMYbv7b+4ldeghMrI1x8jHvj1rUI6TZEJo1qBzvdEqPnrUJuSazVqvKMaDbkl p9wzgAtJ7SRK8b1r9xQ2VnQ/8GjR3CUwcRCKlM7rFVj64PoOjY1r1wjOcuptmXa7 LynYeXiOUYZNs7mqP3Jzwnf5O310YQ== =S8+B -----END PGP SIGNATURE----- --35zwmrjw4ehyged7--