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 X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C30DEC4338F for ; Tue, 27 Jul 2021 06:47:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A250461108 for ; Tue, 27 Jul 2021 06:47:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235638AbhG0Gru (ORCPT ); Tue, 27 Jul 2021 02:47:50 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:59790 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235296AbhG0Grs (ORCPT ); Tue, 27 Jul 2021 02:47:48 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 9C02B22106; Tue, 27 Jul 2021 06:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1627368467; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=XzoDRt4O83/EYGv/WuJBa4qe/fT4Mky56nzFc8R987g=; b=AHLjbmRmhNM23ZCoVwvRpM1sayHPmNAUCkKHJ6g7uGSjhLoRHU+yTeyvAA3ey8jJb2RU0w LKR2d9LwX0lEtPFSeRygTdFq1k25AvU2DALdUzNXrB5y/BHCxjrYW/udE2qDYZAEWXDOsb uJ7E5kxr9ceJ6U0SikW2Y5ZNTq43UHk= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1627368467; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=XzoDRt4O83/EYGv/WuJBa4qe/fT4Mky56nzFc8R987g=; b=MNDVyg7vE9NryVFzzkZ4xPw/loLXSJWasBTVGYSz9An/FzkM29OW+PhcnqNEHohGTHWxBB ri9YLxNGMOA0CHCg== Received: from alsa1.suse.de (alsa1.suse.de [10.160.4.42]) by relay2.suse.de (Postfix) with ESMTP id 881D2A3B87; Tue, 27 Jul 2021 06:47:47 +0000 (UTC) Date: Tue, 27 Jul 2021 08:47:47 +0200 Message-ID: From: Takashi Iwai To: Vitaly Rodionov Cc: Jaroslav Kysela , Takashi Iwai , , , , Lucas Tanure Subject: Re: [PATCH 13/27] ALSA: hda/cs8409: Dont disable I2C clock between consecutive accesses In-Reply-To: <20210726174640.6390-14-vitalyr@opensource.cirrus.com> References: <20210726174640.6390-1-vitalyr@opensource.cirrus.com> <20210726174640.6390-14-vitalyr@opensource.cirrus.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 26 Jul 2021 19:46:26 +0200, Vitaly Rodionov wrote: > > From: Lucas Tanure > > Only disable I2C clock 25 ms after not being used This is error-prone and might be racy, I'm afraid. e.g. the offloaded work isn't canceled when unbinding the driver, so it'll lead to a use-after-free. And the work doesn't take a mutex so it may conflict with re-enabling side. Above all, there is no description "why" this has to be done so. Is it about the performance, or any other reason? thanks, Takashi > > Signed-off-by: Lucas Tanure > Signed-off-by: Vitaly Rodionov > --- > sound/pci/hda/patch_cs8409.c | 42 +++++++++++++++++++++++------------- > sound/pci/hda/patch_cs8409.h | 4 ++++ > 2 files changed, 31 insertions(+), 15 deletions(-) > > diff --git a/sound/pci/hda/patch_cs8409.c b/sound/pci/hda/patch_cs8409.c > index 08205c19698c..335bcdc69106 100644 > --- a/sound/pci/hda/patch_cs8409.c > +++ b/sound/pci/hda/patch_cs8409.c > @@ -53,6 +53,7 @@ static struct cs8409_spec *cs8409_alloc_spec(struct hda_codec *codec) > if (!spec) > return NULL; > codec->spec = spec; > + spec->codec = codec; > codec->power_save_node = 1; > snd_hda_gen_spec_init(&spec->gen); > > @@ -72,21 +73,34 @@ static inline void cs8409_vendor_coef_set(struct hda_codec *codec, unsigned int > snd_hda_codec_write(codec, CS8409_PIN_VENDOR_WIDGET, 0, AC_VERB_SET_PROC_COEF, coef); > } > > -/** > +/* > + * cs8409_disable_i2c_clock - Worker that disable the I2C Clock after 25ms without use > + */ > +static void cs8409_disable_i2c_clock(struct work_struct *work) > +{ > + struct cs8409_spec *spec = container_of(work, struct cs8409_spec, i2c_clk_work.work); > + > + cs8409_vendor_coef_set(spec->codec, 0x0, > + cs8409_vendor_coef_get(spec->codec, 0x0) & 0xfffffff7); > + spec->i2c_clck_enabled = 0; > +} > + > +/* > * cs8409_enable_i2c_clock - Enable I2C clocks > * @codec: the codec instance > - * @enable: Enable or disable I2C clocks > - * > * Enable or Disable I2C clocks. > */ > -static void cs8409_enable_i2c_clock(struct hda_codec *codec, unsigned int enable) > +static void cs8409_enable_i2c_clock(struct hda_codec *codec) > { > - unsigned int retval; > - unsigned int newval; > + struct cs8409_spec *spec = codec->spec; > + > + cancel_delayed_work_sync(&spec->i2c_clk_work); > > - retval = cs8409_vendor_coef_get(codec, 0x0); > - newval = (enable) ? (retval | 0x8) : (retval & 0xfffffff7); > - cs8409_vendor_coef_set(codec, 0x0, newval); > + if (!spec->i2c_clck_enabled) { > + cs8409_vendor_coef_set(codec, 0x0, cs8409_vendor_coef_get(codec, 0x0) | 0x8); > + spec->i2c_clck_enabled = 1; > + } > + queue_delayed_work(system_power_efficient_wq, &spec->i2c_clk_work, msecs_to_jiffies(25)); > } > > /** > @@ -134,7 +148,7 @@ static int cs8409_i2c_read(struct hda_codec *codec, unsigned int i2c_address, un > if (spec->cs42l42_suspended) > return -EPERM; > > - cs8409_enable_i2c_clock(codec, 1); > + cs8409_enable_i2c_clock(codec); > cs8409_vendor_coef_set(codec, CS8409_I2C_ADDR, i2c_address); > > if (paged) { > @@ -157,8 +171,6 @@ static int cs8409_i2c_read(struct hda_codec *codec, unsigned int i2c_address, un > /* Register in bits 15-8 and the data in 7-0 */ > read_data = cs8409_vendor_coef_get(codec, CS8409_I2C_QREAD); > > - cs8409_enable_i2c_clock(codec, 0); > - > return read_data & 0x0ff; > } > > @@ -182,7 +194,7 @@ static int cs8409_i2c_write(struct hda_codec *codec, unsigned int i2c_address, u > if (spec->cs42l42_suspended) > return -EPERM; > > - cs8409_enable_i2c_clock(codec, 1); > + cs8409_enable_i2c_clock(codec); > cs8409_vendor_coef_set(codec, CS8409_I2C_ADDR, i2c_address); > > if (paged) { > @@ -203,8 +215,6 @@ static int cs8409_i2c_write(struct hda_codec *codec, unsigned int i2c_address, u > return -EIO; > } > > - cs8409_enable_i2c_clock(codec, 0); > - > return 0; > } > > @@ -705,6 +715,8 @@ void cs8409_cs42l42_fixups(struct hda_codec *codec, const struct hda_fixup *fix, > spec->cs42l42_mic_jack_in = 0; > spec->cs42l42_suspended = 1; > > + INIT_DELAYED_WORK(&spec->i2c_clk_work, cs8409_disable_i2c_clock); > + > /* Basic initial sequence for specific hw configuration */ > snd_hda_sequence_write(codec, cs8409_cs42l42_init_verbs); > > diff --git a/sound/pci/hda/patch_cs8409.h b/sound/pci/hda/patch_cs8409.h > index bf0e8a4cc4cc..542582c213d2 100644 > --- a/sound/pci/hda/patch_cs8409.h > +++ b/sound/pci/hda/patch_cs8409.h > @@ -11,6 +11,7 @@ > > #include > #include > +#include > #include > #include "hda_local.h" > #include "hda_auto_parser.h" > @@ -267,6 +268,7 @@ struct cs8409_cir_param { > > struct cs8409_spec { > struct hda_gen_spec gen; > + struct hda_codec *codec; > > unsigned int gpio_mask; > unsigned int gpio_dir; > @@ -278,6 +280,8 @@ struct cs8409_spec { > s8 vol[CS42L42_VOLUMES]; > > struct mutex cs8409_i2c_mux; > + unsigned int i2c_clck_enabled; > + struct delayed_work i2c_clk_work; > > /* verb exec op override */ > int (*exec_verb)(struct hdac_device *dev, unsigned int cmd, unsigned int flags, > -- > 2.25.1 >