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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 0AD89C04FF3 for ; Mon, 24 May 2021 07:01:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB2696109F for ; Mon, 24 May 2021 07:01:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232128AbhEXHDU (ORCPT ); Mon, 24 May 2021 03:03:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:33466 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232120AbhEXHDU (ORCPT ); Mon, 24 May 2021 03:03:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A49BC60FEF; Mon, 24 May 2021 07:01:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621839711; bh=wae65KOcaAEsmwm5b4JIWjciQ5lLGB76byDWItyOH48=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=onN/sezX1sshCB0mmiddosdsLbGt4B1DkCIccD2p67O+zB5zG/SovvP30Nnq/FAV5 IKmn6cw0aUb8PVl8AUXmDWSJwgT2sLEeY3Th7bfUjNPc5S13gYQgecadGH04/WsoCM +lbTia6B1epI5dz9xhdKceX2Y4kkM+PvXcrqi7yk= Date: Mon, 24 May 2021 09:01:49 +0200 From: Greg KH To: Baochen Qiang Cc: manivannan.sadhasivam@linaro.org, hemantk@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, ath11k@lists.infradead.org, stable@vger.kernel.org Subject: Re: [PATCH v2] bus: mhi: Wait for M2 state during system resume Message-ID: References: <20210524040312.14409-1-bqiang@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210524040312.14409-1-bqiang@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Mon, May 24, 2021 at 12:03:12PM +0800, Baochen Qiang wrote: > During system resume, MHI host triggers M3->M0 transition and then waits > for target device to enter M0 state. Once done, the device queues a state > change event into ctrl event ring and notifies MHI host by raising an > interrupt, where a tasklet is scheduled to process this event. In most cases, > the tasklet is served timely and wait operation succeeds. > > However, there are cases where CPU is busy and cannot serve this tasklet > for some time. Once delay goes long enough, the device moves itself to M1 > state and also interrupts MHI host after inserting a new state change > event to ctrl ring. Later CPU finally has time to process the ring, however > there are two events in it now: > 1. for M3->M0 event, which is processed first as queued first, > tasklet handler updates device state to M0 and wakes up the task, > i.e., the MHI host. > 2. for M0->M1 event, which is processed later, tasklet handler > triggers M1->M2 transition and updates device state to M2 directly, > then wakes up the MHI host(if still sleeping on this wait queue). > Note that although MHI host has been woken up while processing the first > event, it may still has no chance to run before the second event is processed. > In other words, MHI host has to keep waiting till timeout cause the M0 state > has been missed. > > kernel log here: > ... > Apr 15 01:45:14 test-NUC8i7HVK kernel: [ 4247.911251] mhi 0000:06:00.0: Entered with PM state: M3, MHI state: M3 > Apr 15 01:45:14 test-NUC8i7HVK kernel: [ 4247.917762] mhi 0000:06:00.0: State change event to state: M0 > Apr 15 01:45:14 test-NUC8i7HVK kernel: [ 4247.917767] mhi 0000:06:00.0: State change event to state: M1 > Apr 15 01:45:14 test-NUC8i7HVK kernel: [ 4338.788231] mhi 0000:06:00.0: Did not enter M0 state, MHI state: M2, PM state: M2 > ... > > Fix this issue by simply adding M2 as a valid state for resume. > > Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-01720.1-QCAHSPSWPL_V1_V2_SILICONZ_LITE-1 > > Fixes: 0c6b20a1d720 ("bus: mhi: core: Add support for MHI suspend and resume") > Signed-off-by: Baochen Qiang > Reviewed-by: Hemant Kumar > --- > drivers/bus/mhi/core/pm.c | 1 + > 1 file changed, 1 insertion(+) This is not the correct way to submit patches for inclusion in the stable kernel tree. Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.