Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755620Ab3GBU1X (ORCPT ); Tue, 2 Jul 2013 16:27:23 -0400 Received: from mga14.intel.com ([143.182.124.37]:60256 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754860Ab3GBU1T (ORCPT ); Tue, 2 Jul 2013 16:27:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,983,1363158000"; d="scan'208";a="263261115" Date: Tue, 2 Jul 2013 23:31:17 +0300 From: Mika Westerberg To: "Rafael J. Wysocki" Cc: Bjorn Helgaas , "Kirill A. Shutemov" , Greg Kroah-Hartman , "Rafael J. Wysocki" , Jesse Barnes , Yinghai Lu , "Ronciak, John" , "Penner, Miles J" , Bruce Allan , Heikki Krogerus , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "x86@kernel.org" Subject: Re: [PATCH 1/6] PCI: acpiphp: do not check for SLOT_ENABLED in enable_device() Message-ID: <20130702203117.GT9294@intel.com> References: <1372177330-28013-1-git-send-email-mika.westerberg@linux.intel.com> <3216917.m2IEX2IHod@vostro.rjw.lan> <4523014.G6VJLhZf81@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4523014.G6VJLhZf81@vostro.rjw.lan> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1876 Lines: 36 On Tue, Jul 02, 2013 at 10:29:12PM +0200, Rafael J. Wysocki wrote: > On Tuesday, July 02, 2013 10:40:39 AM Bjorn Helgaas wrote: > > On Mon, Jul 1, 2013 at 7:29 PM, Rafael J. Wysocki wrote: > > > On Monday, July 01, 2013 09:36:13 PM Mika Westerberg wrote: > > >> On Mon, Jul 01, 2013 at 04:01:37PM +0200, Rafael J. Wysocki wrote: > > >> > > Given the fact that SLOT_ENABLED is only checked in acpiphp_enable_slot() > > >> > > (after this patch) and that /sys/bus/pci/slots/*/power uses SLOT_POWEREDON > > >> > > anyway, should we remove the whole flag? > > >> > > > >> > Sure, if it is not necessary any more, we should remove it. > > >> > > >> Well, there is one thing that changes due that. Once the flag is gone > > >> userspace can do 'echo 1 > /sys/bus/pci/slots/*/power' several times and > > >> the slot is always re-enumerated. > > >> > > >> If that is not acceptable we should probably move the SLOT_ENABLED check > > >> closer to acpiphp_core:enable_device() and drop it from here, so that we > > >> always re-enumerate on Bus Check event but userspace can only do enable > > >> once (we still re-enumerate on Bus Check). > > > > > > Yes, that sounds like the right thing to do. > > > > Is it actually a problem if we re-enumerate every time userspace does > > 'echo 1 > /sys/bus/pci/slots/*/power'? I assume re-enumeration is a > > no-op if nothing has changed. > > Well, if it's a no-op in that case, then re-enumerating shouldn't be a problem, > but is it a no-op? I can confirm that it's a no-op (at least for the Thunderbolt case). Basically we just scan for new devices and nothing is to be found. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/