From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71DF4C433EF for ; Thu, 21 Oct 2021 00:25:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5C66B60FED for ; Thu, 21 Oct 2021 00:25:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232432AbhJUA1Q (ORCPT ); Wed, 20 Oct 2021 20:27:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:45728 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232468AbhJUA0N (ORCPT ); Wed, 20 Oct 2021 20:26:13 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B4EF16121E; Thu, 21 Oct 2021 00:23:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634775837; bh=u17dEBACuhhNVBqaU2GsXt7cKqeBlviZJa2K65iEX3A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rlnRBjSrmzDrFVH/PSJI9J4IpxuBYesxBzyKwueLL1MNcqqvJ4RWY3H3PPWNmwOYk lrOix99EtFNoXZcNyq8EmPtaPUJ8DFtqEaqJ6HNudAJ/v73bNG3SxDsZBQbUQ6PF5k E7K+5idqaUvpsw6hK1owc1AKO68FpJxwZFzmxK/xZXcV9fNLVQuaI7r8hDy+KZP/xG ERaxj55FBxLs+HKPqi5lVIiytouget4IXPqAbXwtdLT/nzCEFCsp1KYqSn5bf9ABgm lu0q7Utna36QjqZ+YwpTmJlt8luQ5J9DGd1NMa5VA1qvVbRZkAwb+Ep3dXH3XMUYJu uammQKQ4hMuqg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kai Vehmanen , Takashi Iwai , Sasha Levin , perex@perex.cz, tiwai@suse.com, broonie@kernel.org, ranjani.sridharan@linux.intel.com, alsa-devel@alsa-project.org Subject: [PATCH AUTOSEL 4.14 8/9] ALSA: hda: avoid write to STATESTS if controller is in reset Date: Wed, 20 Oct 2021 20:23:32 -0400 Message-Id: <20211021002333.1129824-8-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211021002333.1129824-1-sashal@kernel.org> References: <20211021002333.1129824-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kai Vehmanen [ Upstream commit b37a15188eae9d4c49c5bb035e0c8d4058e4d9b3 ] The snd_hdac_bus_reset_link() contains logic to clear STATESTS register before performing controller reset. This code dates back to an old bugfix in commit e8a7f136f5ed ("[ALSA] hda-intel - Improve HD-audio codec probing robustness"). Originally the code was added to azx_reset(). The code was moved around in commit a41d122449be ("ALSA: hda - Embed bus into controller object") and ended up to snd_hdac_bus_reset_link() and called primarily via snd_hdac_bus_init_chip(). The logic to clear STATESTS is correct when snd_hdac_bus_init_chip() is called when controller is not in reset. In this case, STATESTS can be cleared. This can be useful e.g. when forcing a controller reset to retry codec probe. A normal non-power-on reset will not clear the bits. However, this old logic is problematic when controller is already in reset. The HDA specification states that controller must be taken out of reset before writing to registers other than GCTL.CRST (1.0a spec, 3.3.7). The write to STATESTS in snd_hdac_bus_reset_link() will be lost if the controller is already in reset per the HDA specification mentioned. This has been harmless on older hardware. On newer generation of Intel PCIe based HDA controllers, if configured to report issues, this write will emit an unsupported request error. If ACPI Platform Error Interface (APEI) is enabled in kernel, this will end up to kernel log. Fix the code in snd_hdac_bus_reset_link() to only clear the STATESTS if the function is called when controller is not in reset. Otherwise clearing the bits is not possible and should be skipped. Signed-off-by: Kai Vehmanen Link: https://lore.kernel.org/r/20211012142935.3731820-1-kai.vehmanen@linux.intel.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/hda/hdac_controller.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/sound/hda/hdac_controller.c b/sound/hda/hdac_controller.c index 778b42ba90b8..5ae72134159a 100644 --- a/sound/hda/hdac_controller.c +++ b/sound/hda/hdac_controller.c @@ -389,8 +389,9 @@ int snd_hdac_bus_reset_link(struct hdac_bus *bus, bool full_reset) if (!full_reset) goto skip_reset; - /* clear STATESTS */ - snd_hdac_chip_writew(bus, STATESTS, STATESTS_INT_MASK); + /* clear STATESTS if not in reset */ + if (snd_hdac_chip_readb(bus, GCTL) & AZX_GCTL_RESET) + snd_hdac_chip_writew(bus, STATESTS, STATESTS_INT_MASK); /* reset controller */ snd_hdac_bus_enter_link_reset(bus); -- 2.33.0