Received: by 2002:a05:6a10:5bc5:0:0:0:0 with SMTP id os5csp2974093pxb; Mon, 18 Oct 2021 05:54:39 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxyxlkjB9Q13XjAtKa0u2gacQZNR14uJYxXQjEYtIorT82s1Ik7Zsa3bnS3+2k1xcW0GUGI X-Received: by 2002:a63:5604:: with SMTP id k4mr23880633pgb.340.1634561679810; Mon, 18 Oct 2021 05:54:39 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1634561679; cv=none; d=google.com; s=arc-20160816; b=LQpRojtGWH+TI3o7HMZgWzDexe+ENaJfwrs4yGv2xFgH0hB3NkmGQ2PtZQZZqtFSSM jGsNOgr+ZQ0u4E0+sdy5PBABiLw0ED1J/bZF347PlfNI3A2KA9btnU46qDhPi6GBZAEx ccGRJnJwPKUdZuEN/p6iH2a/IaO4EWX3EtMueFrzTnll8vldExJxvEDMR98zFKXMyUyY Km9n5sTbo3CmjqRXSGPajVVXFGHqblRgot+6LACMu9Guqi6TK3rJCQlnvD4j0MeZYmxE KVnpcUHeIEavjsbsXerGHShAxVvPkOgTOvJiZNNIqVVSqlMNs1a3R+r0zwmYOUvppeTg uUMQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:date:message-id:user-agent:cc:to:references :in-reply-to:from:subject:content-transfer-encoding:mime-version :dmarc-filter:sender:dkim-signature; bh=RnKubHLBxsURiKk2HojMzMbLeWSvD8hkXWqctYdrYCU=; b=CZqkFsgOVcoSvhE37PQmw1/lI1WyhMzboCbHmmj2TLUmt77HYLKvt8VDzKPd5BfZ8o +b8eBVBE3a4uBoWvQ8Y/IOFMbsCtsW48t6IHKzxZqn4cuOd+rmf2kjpKBcZN7+8QpVDG 6fToy63nnCraO0j+zZ/uxWryYH7dUVF1aYYn4lgbC8QwQIiOXpceBHL++nLUEB4fNYU/ RrCmCZUdxlzX9Yah+Rv9lVVFxJrj/S1hUSsbsgahXuj+TteKskl45p6Keg/yUVXtb4dE 6d8NK9R+IFR+LCBVAnPe3cD9J2hOnlrM7UN92AnaZKk65UpG9P+A9pFaWtA5rXeAZ5YF FrYQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@mg.codeaurora.org header.s=smtp header.b=teQlPUV7; spf=pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-wireless-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id bc12si8264858plb.31.2021.10.18.05.54.30; Mon, 18 Oct 2021 05:54:39 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@mg.codeaurora.org header.s=smtp header.b=teQlPUV7; spf=pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-wireless-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231565AbhJRM3x (ORCPT + 64 others); Mon, 18 Oct 2021 08:29:53 -0400 Received: from so254-9.mailgun.net ([198.61.254.9]:29474 "EHLO so254-9.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231493AbhJRM3w (ORCPT ); Mon, 18 Oct 2021 08:29:52 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1634560061; h=Date: Message-ID: Cc: To: References: In-Reply-To: From: Subject: Content-Transfer-Encoding: MIME-Version: Content-Type: Sender; bh=RnKubHLBxsURiKk2HojMzMbLeWSvD8hkXWqctYdrYCU=; b=teQlPUV79NuU3t20Icdz6fME80ajitnbTNYHewUfd+uBJsKGgwP18i7jpfZwXF+5WGanXWPx JPUVscNZLbmhJX7h35j3yIW4qdRETlWaKlouiVW/WpfyX6KzfCLl4gi1be2hID6C+VLF+GKY eh0hUQ6vc8VeMfjxl35CZcaruxA= X-Mailgun-Sending-Ip: 198.61.254.9 X-Mailgun-Sid: WyI3YTAwOSIsICJsaW51eC13aXJlbGVzc0B2Z2VyLmtlcm5lbC5vcmciLCAiYmU5ZTRhIl0= Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n05.prod.us-east-1.postgun.com with SMTP id 616d682cab9da96e64d7dbc9 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 18 Oct 2021 12:27:24 GMT Sender: kvalo=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 3B46AC43617; Mon, 18 Oct 2021 12:27:24 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-caf-mail-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.5 required=2.0 tests=ALL_TRUSTED,BAYES_00, MISSING_DATE,SPF_FAIL autolearn=no autolearn_force=no version=3.4.0 Received: from tykki.adurom.net (tynnyri.adurom.net [51.15.11.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: kvalo) by smtp.codeaurora.org (Postfix) with ESMTPSA id D3172C4338F; Mon, 18 Oct 2021 12:27:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 smtp.codeaurora.org D3172C4338F Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=codeaurora.org Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH] mwifiex: Add quirk resetting the PCI bridge on MS Surface devices From: Kalle Valo In-Reply-To: <20211011134238.16551-1-verdre@v0yd.nl> References: <20211011134238.16551-1-verdre@v0yd.nl> To: =?utf-8?q?Jonas_Dre=C3=9Fler?= Cc: Amitkumar Karwar , Ganapathi Bhat , Xinming Hu , "David S. Miller" , Jakub Kicinski , =?utf-8?q?Jonas_Dre=C3=9Fler?= , Tsuchiya Yuto , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, Maximilian Luz , Andy Shevchenko , Bjorn Helgaas , =?utf-8?q?Pali_Roh=C3=A1r?= , Heiner Kallweit , Johannes Berg , Brian Norris , David Laight User-Agent: pwcli/0.1.0-git (https://github.com/kvalo/pwcli/) Python/3.7.3 Message-ID: <163456003528.19217.10035499117616642207.kvalo@codeaurora.org> Date: Mon, 18 Oct 2021 12:27:24 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Jonas Dreßler wrote: > The most recent firmware (15.68.19.p21) of the 88W8897 PCIe+USB card > reports a hardcoded LTR value to the system during initialization, > probably as an (unsuccessful) attempt of the developers to fix firmware > crashes. This LTR value prevents most of the Microsoft Surface devices > from entering deep powersaving states (either platform C-State 10 or > S0ix state), because the exit latency of that state would be higher than > what the card can tolerate. > > Turns out the card works just the same (including the firmware crashes) > no matter if that hardcoded LTR value is reported or not, so it's kind > of useless and only prevents us from saving power. > > To get rid of those hardcoded LTR requirements, it's possible to reset > the PCI bridge device after initializing the cards firmware. I'm not > exactly sure why that works, maybe the power management subsystem of the > PCH resets its stored LTR values when doing a function level reset of > the bridge device. Doing the reset once after starting the wifi firmware > works very well, probably because the firmware only reports that LTR > value a single time during firmware startup. > > Signed-off-by: Jonas Dreßler I'm not sure what was the conclusion from the discussion, so dropping the patch. Please resend once it's ready to be applied. Patch set to Changes Requested. -- https://patchwork.kernel.org/project/linux-wireless/patch/20211011134238.16551-1-verdre@v0yd.nl/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches