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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 AF5ECC433E2 for ; Tue, 15 Sep 2020 08:25:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65EF6221E5 for ; Tue, 15 Sep 2020 08:25:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="CpSeLpdD"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="TJARyVS8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726440AbgIOIZP (ORCPT ); Tue, 15 Sep 2020 04:25:15 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:40342 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726122AbgIOIM7 (ORCPT ); Tue, 15 Sep 2020 04:12:59 -0400 Date: Tue, 15 Sep 2020 10:12:54 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1600157575; h=from:from:reply-to:subject:subject: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=df2KM6FrDujliKQ7wiOtr/3jSderU/hQhzxC8Z1rOi4=; b=CpSeLpdDnyvJs2RFI8JmdglWsneT0n1hl6I5+u+zEVfe3KDLkPeppCvTYQasHicq1PLOFz GXKmbMqL5B17ngvGW9qcphFMB1CkuPHtx6RR2NQqNHEGgtZtV2CTmQ22XCXcid9hOcsofQ 6vtBbANgzxGMfvuxofKtp53/uUc8EfRlplFn0BXmmy9Uc+zjf37TgNj6lkZZYMUDoYhnxe wv7rEXeIObxAIeVmgJNSocyw0IIPsCgg6krEp9+nNOIxq3deY1iTmZxGCgeQ4gbdElnVF3 8ysLqUG7cEIe+XCcQQF+QcY/EvPlBYIpHaq9FPj+9pDpu9sH3OHa/V2rP4F5pg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1600157575; h=from:from:reply-to:subject:subject: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=df2KM6FrDujliKQ7wiOtr/3jSderU/hQhzxC8Z1rOi4=; b=TJARyVS8WJd5AckJ3ICljUj08Kfru8o8lrETsGgtiI5zh8TMRT/+IDA1Mc3XLriDaGw17o PRfZOIGlsINhLIDg== From: Sebastian Andrzej Siewior To: Jeaho Hwang Cc: linux-rt-users@vger.kernel.org Subject: Re: "RTOS unfriendly" in chipidea udc code Message-ID: <20200915081254.urefcscoqe42rglg@linutronix.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On 2020-09-14 10:01:46 [+0900], Jeaho Hwang wrote: > The function hw_usb_reset, called by isr_reset_handler, is using > udelay to wait hw reset and commented "RTOS unfriendly". Can I be sure > RT-safe is it? Could you suggest any better alternative? If I traced it right, that function is used as an interrupt handler which should run threaded on PREEMPT_RT (it should be requested via request_irq() or so). That means that the udelay() can be preempted by a task with higher priority. > Thanks. Regards Sebastian