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=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED 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 56B1DECDE5F for ; Mon, 23 Jul 2018 20:22:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 062F620856 for ; Mon, 23 Jul 2018 20:22:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="JeRGBDCW"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="JeRGBDCW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 062F620856 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388113AbeGWVZo (ORCPT ); Mon, 23 Jul 2018 17:25:44 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:50142 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388029AbeGWVZn (ORCPT ); Mon, 23 Jul 2018 17:25:43 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id DA6D760B11; Mon, 23 Jul 2018 20:22:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1532377371; bh=bU+CKgAwEsEWCzrRu3uCoYtA5OT91d0Vh9r+FNoGh/o=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=JeRGBDCWdwfVnkpSOoIjjSBUv8izcR6Y+wSJ7fN/AsBsnjLm2CHOobTLnoSjwBU0t iYk6VRlHE6GcEQkwLkiMxW4otZmmwzFE7LrZRjbWhKD6m2ymlJ0SE4WfaiDljhpg8s R3FXySe7wQhoNy73qXpBcYws4I7UEW9+Q9G7rMHE= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 05A046021A; Mon, 23 Jul 2018 20:22:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1532377371; bh=bU+CKgAwEsEWCzrRu3uCoYtA5OT91d0Vh9r+FNoGh/o=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=JeRGBDCWdwfVnkpSOoIjjSBUv8izcR6Y+wSJ7fN/AsBsnjLm2CHOobTLnoSjwBU0t iYk6VRlHE6GcEQkwLkiMxW4otZmmwzFE7LrZRjbWhKD6m2ymlJ0SE4WfaiDljhpg8s R3FXySe7wQhoNy73qXpBcYws4I7UEW9+Q9G7rMHE= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 23 Jul 2018 13:22:50 -0700 From: rishabhb@codeaurora.org To: "Rafael J. Wysocki" Cc: Greg Kroah-Hartman , Linux Kernel Mailing List , ckadabi@codeaurora.org, tsoni@codeaurora.org, Vikram Mulukutla , rjwysocki@gmail.com Subject: Re: [PATCH] dd: Invoke one probe retry cycle after every initcall level In-Reply-To: References: <1532035440-7860-1-git-send-email-rishabhb@codeaurora.org> Message-ID: X-Sender: rishabhb@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-07-23 04:17, Rafael J. Wysocki wrote: > On Thu, Jul 19, 2018 at 11:24 PM, Rishabh Bhatnagar > wrote: >> Drivers that are registered at an initcall level may have to >> wait until late_init before the probe deferral mechanism can >> retry their probe functions. It is possible that their >> dependencies were resolved much earlier, in some cases even >> before the next initcall level. Invoke one probe retry cycle >> at every _sync initcall level, allowing these drivers to be >> probed earlier. > > Can you please say something about the actual use case this is > expected to address? We have a display driver that depends 3 other devices to be probed so that it can bring-up the display. Because of dependencies not being met the deferral mechanism defers the probes for a later time, even though the dependencies might be met earlier. With this change display can be brought up much earlier. > >> Signed-off-by: Vikram Mulukutla >> Signed-off-by: Rishabh Bhatnagar >> --- >> drivers/base/dd.c | 33 +++++++++++++++++++++++++++------ >> 1 file changed, 27 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/base/dd.c b/drivers/base/dd.c >> index 1435d72..e6a6821 100644 >> --- a/drivers/base/dd.c >> +++ b/drivers/base/dd.c >> @@ -224,23 +224,44 @@ void device_unblock_probing(void) >> driver_deferred_probe_trigger(); >> } >> >> +static void enable_trigger_defer_cycle(void) >> +{ >> + driver_deferred_probe_enable = true; >> + driver_deferred_probe_trigger(); >> + /* >> + * Sort as many dependencies as possible before the next >> initcall >> + * level >> + */ >> + flush_work(&deferred_probe_work); >> +} >> + >> /** >> * deferred_probe_initcall() - Enable probing of deferred devices >> * >> * We don't want to get in the way when the bulk of drivers are >> getting probed. >> * Instead, this initcall makes sure that deferred probing is delayed >> until >> - * late_initcall time. >> + * all the registered initcall functions at a particular level are >> completed. >> + * This function is invoked at every *_initcall_sync level. >> */ >> static int deferred_probe_initcall(void) >> { >> - driver_deferred_probe_enable = true; >> - driver_deferred_probe_trigger(); >> - /* Sort as many dependencies as possible before exiting >> initcalls */ >> - flush_work(&deferred_probe_work); >> + enable_trigger_defer_cycle(); >> + driver_deferred_probe_enable = false; >> + return 0; >> +} >> +arch_initcall_sync(deferred_probe_initcall); >> +subsys_initcall_sync(deferred_probe_initcall); >> +fs_initcall_sync(deferred_probe_initcall); >> +device_initcall_sync(deferred_probe_initcall); >> + >> +static int deferred_probe_enable_fn(void) >> +{ >> + /* Enable deferred probing for all time */ >> + enable_trigger_defer_cycle(); >> initcalls_done = true; >> return 0; >> } >> -late_initcall(deferred_probe_initcall); >> +late_initcall(deferred_probe_enable_fn); >> >> /** >> * device_is_bound() - Check if device is bound to a driver >> -- >> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora >> Forum, >> a Linux Foundation Collaborative Project