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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 ED5B2C28CC1 for ; Thu, 30 May 2019 03:24:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C755A24A58 for ; Thu, 30 May 2019 03:24:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559186678; bh=9IM83kU3WNfz0QfBh+pLawTB58Dclw0rzHSXeY6vPLk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OA6C4r8P/imias9wjO5Vv1LJVlRDeco8ABEdGP4bIp6523tebHW3k7WgBCfKqymZI k6gJEAMujL1kbGHDE3ANzmoFrZt2XfwV7kTzedekGDfQ9GwlAG9egVsukHyQpCA0bg fegSRxzJLuvevAeMUp2cPhU4awY2jxSOtQcwEFv0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387412AbfE3DYh (ORCPT ); Wed, 29 May 2019 23:24:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:50012 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731469AbfE3DSN (ORCPT ); Wed, 29 May 2019 23:18:13 -0400 Received: from localhost (ip67-88-213-2.z213-88-67.customer.algx.net [67.88.213.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0D06824789; Thu, 30 May 2019 03:18:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559186293; bh=9IM83kU3WNfz0QfBh+pLawTB58Dclw0rzHSXeY6vPLk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YZFNpbTrzv+msJiRdWF513oBMKvAe/7QEFgrqzZXQkIcPhKEXCmcvBgbOB8tBMA3J +1swqqYeOwdGRZROX6m+WHMJ/N1+z+5jBhagVCaysgoLNCk8w49XNTZMRAom6fSMCK G4xHfnQIoTw/peu1luXH+iBprhAAg/X05YoXpB1c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Hutchinson , Antti Palosaari , Sean Young , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 4.19 251/276] media: m88ds3103: serialize reset messages in m88ds3103_set_frontend Date: Wed, 29 May 2019 20:06:49 -0700 Message-Id: <20190530030540.838285379@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530030523.133519668@linuxfoundation.org> References: <20190530030523.133519668@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 981fbe3da20a6f35f17977453bce7dfc1664d74f ] Ref: https://bugzilla.kernel.org/show_bug.cgi?id=199323 Users are experiencing problems with the DVBSky S960/S960C USB devices since the following commit: 9d659ae: ("locking/mutex: Add lock handoff to avoid starvation") The device malfunctions after running for an indeterminable period of time, and the problem can only be cleared by rebooting the machine. It is possible to encourage the problem to surface by blocking the signal to the LNB. Further debugging revealed the cause of the problem. In the following capture: - thread #1325 is running m88ds3103_set_frontend - thread #42 is running ts2020_stat_work a> [1325] usb 1-1: dvb_usb_v2_generic_io: >>> 08 68 02 07 80 [1325] usb 1-1: dvb_usb_v2_generic_io: <<< 08 [42] usb 1-1: dvb_usb_v2_generic_io: >>> 09 01 01 68 3f [42] usb 1-1: dvb_usb_v2_generic_io: <<< 08 ff [42] usb 1-1: dvb_usb_v2_generic_io: >>> 08 68 02 03 11 [42] usb 1-1: dvb_usb_v2_generic_io: <<< 07 [42] usb 1-1: dvb_usb_v2_generic_io: >>> 09 01 01 60 3d [42] usb 1-1: dvb_usb_v2_generic_io: <<< 07 ff b> [1325] usb 1-1: dvb_usb_v2_generic_io: >>> 08 68 02 07 00 [1325] usb 1-1: dvb_usb_v2_generic_io: <<< 07 [42] usb 1-1: dvb_usb_v2_generic_io: >>> 08 68 02 03 11 [42] usb 1-1: dvb_usb_v2_generic_io: <<< 07 [42] usb 1-1: dvb_usb_v2_generic_io: >>> 09 01 01 60 21 [42] usb 1-1: dvb_usb_v2_generic_io: <<< 07 ff [42] usb 1-1: dvb_usb_v2_generic_io: >>> 08 68 02 03 11 [42] usb 1-1: dvb_usb_v2_generic_io: <<< 07 [42] usb 1-1: dvb_usb_v2_generic_io: >>> 09 01 01 60 66 [42] usb 1-1: dvb_usb_v2_generic_io: <<< 07 ff [1325] usb 1-1: dvb_usb_v2_generic_io: >>> 08 68 02 03 11 [1325] usb 1-1: dvb_usb_v2_generic_io: <<< 07 [1325] usb 1-1: dvb_usb_v2_generic_io: >>> 08 60 02 10 0b [1325] usb 1-1: dvb_usb_v2_generic_io: <<< 07 Two i2c messages are sent to perform a reset in m88ds3103_set_frontend: a. 0x07, 0x80 b. 0x07, 0x00 However, as shown in the capture, the regmap mutex is being handed over to another thread (ts2020_stat_work) in between these two messages. >>From here, the device responds to every i2c message with an 07 message, and will only return to normal operation following a power cycle. Use regmap_multi_reg_write to group the two reset messages, ensuring both are processed before the regmap mutex is unlocked. Signed-off-by: James Hutchinson Reviewed-by: Antti Palosaari Signed-off-by: Sean Young Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin --- drivers/media/dvb-frontends/m88ds3103.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/media/dvb-frontends/m88ds3103.c b/drivers/media/dvb-frontends/m88ds3103.c index dffd2d4bf1c8b..c25c927974089 100644 --- a/drivers/media/dvb-frontends/m88ds3103.c +++ b/drivers/media/dvb-frontends/m88ds3103.c @@ -309,6 +309,9 @@ static int m88ds3103_set_frontend(struct dvb_frontend *fe) u16 u16tmp; u32 tuner_frequency_khz, target_mclk; s32 s32tmp; + static const struct reg_sequence reset_buf[] = { + {0x07, 0x80}, {0x07, 0x00} + }; dev_dbg(&client->dev, "delivery_system=%d modulation=%d frequency=%u symbol_rate=%d inversion=%d pilot=%d rolloff=%d\n", @@ -321,11 +324,7 @@ static int m88ds3103_set_frontend(struct dvb_frontend *fe) } /* reset */ - ret = regmap_write(dev->regmap, 0x07, 0x80); - if (ret) - goto err; - - ret = regmap_write(dev->regmap, 0x07, 0x00); + ret = regmap_multi_reg_write(dev->regmap, reset_buf, 2); if (ret) goto err; -- 2.20.1