Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753407AbXLJX0v (ORCPT ); Mon, 10 Dec 2007 18:26:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751972AbXLJX0l (ORCPT ); Mon, 10 Dec 2007 18:26:41 -0500 Received: from g1t0028.austin.hp.com ([15.216.28.35]:16693 "EHLO g1t0028.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751835AbXLJX0k (ORCPT ); Mon, 10 Dec 2007 18:26:40 -0500 From: Bjorn Helgaas To: Shaohua Li Subject: Re: RFC: PNP: do not stop/start devices in suspend/resume path Date: Mon, 10 Dec 2007 16:26:34 -0700 User-Agent: KMail/1.9.6 Cc: Jiri Slaby , Andrew Morton , matthew@wil.cx, Linux Kernel Mailing List , linux-pm@lists.linux-foundation.org, drzeus@drzeus.cx, linux-acpi@vger.kernel.org, Adam Belay , Matthieu Castet , Len Brown References: <4745F77C.7040402@gmail.com> <200712051124.18852.bjorn.helgaas@hp.com> <1197011615.21100.1.camel@sli10-desk.sh.intel.com> In-Reply-To: <1197011615.21100.1.camel@sli10-desk.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200712101626.35491.bjorn.helgaas@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2674 Lines: 68 On Friday 07 December 2007 12:13:35 am Shaohua Li wrote: > On Thu, 2007-12-06 at 02:24 +0800, Bjorn Helgaas wrote: > > Index: linux-mm/drivers/pnp/driver.c > > =================================================================== > > --- linux-mm.orig/drivers/pnp/driver.c 2007-11-30 13:58:25.000000000 > > -0700 > > +++ linux-mm/drivers/pnp/driver.c 2007-12-03 09:58:35.000000000 > > -0700 > > @@ -161,13 +161,6 @@ > > return error; > > } > > > > - if (!(pnp_drv->flags & PNP_DRIVER_RES_DO_NOT_CHANGE) && > > - pnp_can_disable(pnp_dev)) { > > - error = pnp_stop_dev(pnp_dev); > > - if (error) > > - return error; > > - } > > - > > if (pnp_dev->protocol && pnp_dev->protocol->suspend) > > pnp_dev->protocol->suspend(pnp_dev, state); > > return 0; > > @@ -177,7 +170,6 @@ > > { > > struct pnp_dev *pnp_dev = to_pnp_dev(dev); > > struct pnp_driver *pnp_drv = pnp_dev->driver; > > - int error; > > > > if (!pnp_drv) > > return 0; > > @@ -185,12 +177,6 @@ > > if (pnp_dev->protocol && pnp_dev->protocol->resume) > > pnp_dev->protocol->resume(pnp_dev); > > > > - if (!(pnp_drv->flags & PNP_DRIVER_RES_DO_NOT_CHANGE)) { > > - error = pnp_start_dev(pnp_dev); > > - if (error) > > - return error; > > - } > > - > I'd suggest keep pnp_start_dev here to prevent BIOS not or assign > different resources after a resume. The patch I currently have in -mm (http://lkml.org/lkml/2007/10/29/412) merely requests resources in pnp_start_dev() and releases them in pnp_stop_dev(). So if we remove pnp_stop_dev() but keep pnp_start_dev(), I have to fix that patch to deal with things that may already be reserved. But I don't see any mention in the spec of running _SRS in the sleep/wakup path, so I'm not convinced it's really necessary. Section 7.4 mentions _TTS, _PTS, _GTS, etc., but not _SRS. For devices, it looks like the intent is that BIOS should generate notifications that cause OSPM to re-enumerate devices that might have changed. I'm pretty sure Linux is missing some of that code, though, so I could believe that _SRS might help paper over that deficiency. What I'd really like to do is figure out how Windows uses _SRS and do the same thing. Bjorn -- 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/