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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA049ECAAD8 for ; Tue, 20 Sep 2022 09:48:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230201AbiITJsB (ORCPT ); Tue, 20 Sep 2022 05:48:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230300AbiITJrx (ORCPT ); Tue, 20 Sep 2022 05:47:53 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F7FD6F554; Tue, 20 Sep 2022 02:47:46 -0700 (PDT) Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MWxV14DnlzpTDQ; Tue, 20 Sep 2022 17:44:57 +0800 (CST) Received: from kwepemm600004.china.huawei.com (7.193.23.242) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 20 Sep 2022 17:47:45 +0800 Received: from localhost.localdomain (10.69.192.56) by kwepemm600004.china.huawei.com (7.193.23.242) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 20 Sep 2022 17:47:44 +0800 From: Huisong Li To: , CC: , , , , , Subject: [PATCH 1/2] ACPI: PCC: replace wait_for_completion() Date: Tue, 20 Sep 2022 17:44:59 +0800 Message-ID: <20220920094500.11283-2-lihuisong@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20220920094500.11283-1-lihuisong@huawei.com> References: <20220920094500.11283-1-lihuisong@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.69.192.56] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemm600004.china.huawei.com (7.193.23.242) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Currently, the function waiting for completion of mailbox operation is 'wait_for_completion()'. The PCC method will be permanently blocked if this mailbox message fails to execute. So this patch replaces it with 'wait_for_completion_timeout()'. And set the timeout interval to an arbitrary retries on top of nominal to prevent the remote processor is slow to respond to PCC commands. Fixes: 77e2a04745ff ("ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype") Signed-off-by: Huisong Li --- drivers/acpi/acpi_pcc.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/acpi_pcc.c b/drivers/acpi/acpi_pcc.c index a12b55d81209..a1052fe998bf 100644 --- a/drivers/acpi/acpi_pcc.c +++ b/drivers/acpi/acpi_pcc.c @@ -23,6 +23,12 @@ #include +/* + * Arbitrary retries in case the remote processor is slow to respond + * to PCC commands + */ +#define PCC_CMD_WAIT_RETRIES_NUM 500 + struct pcc_data { struct pcc_mbox_chan *pcc_chan; void __iomem *pcc_comm_addr; @@ -86,6 +92,7 @@ acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr, { int ret; struct pcc_data *data = region_context; + u64 usecs_lat; reinit_completion(&data->done); @@ -96,8 +103,20 @@ acpi_pcc_address_space_handler(u32 function, acpi_physical_address addr, if (ret < 0) return AE_ERROR; - if (data->pcc_chan->mchan->mbox->txdone_irq) - wait_for_completion(&data->done); + if (data->pcc_chan->mchan->mbox->txdone_irq) { + /* + * pcc_chan->latency is just a Nominal value. In reality the remote + * processor could be much slower to reply. So add an arbitrary + * amount of wait on top of Nominal. + */ + usecs_lat = PCC_CMD_WAIT_RETRIES_NUM * data->pcc_chan->latency; + ret = wait_for_completion_timeout(&data->done, + usecs_to_jiffies(usecs_lat)); + if (ret == 0) { + pr_err("PCC command executed timeout!\n"); + return AE_TIME; + } + } mbox_client_txdone(data->pcc_chan->mchan, ret); -- 2.33.0