Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932408AbVKQQzl (ORCPT ); Thu, 17 Nov 2005 11:55:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932404AbVKQQzl (ORCPT ); Thu, 17 Nov 2005 11:55:41 -0500 Received: from digitalimplant.org ([64.62.235.95]:49572 "HELO digitalimplant.org") by vger.kernel.org with SMTP id S932408AbVKQQzk (ORCPT ); Thu, 17 Nov 2005 11:55:40 -0500 Date: Thu, 17 Nov 2005 08:55:29 -0800 (PST) From: Patrick Mochel X-X-Sender: mochel@monsoon.he.net To: Greg KH cc: Adam Belay , Linux-pm mailing list , "" Subject: Re: [linux-pm] Re: [RFC][PATCH 6/6] PCI PM: pci_save/restore_state improvements In-Reply-To: <20051116180655.GC6908@suse.de> Message-ID: References: <1132111902.9809.59.camel@localhost.localdomain> <20051116063125.GE31375@suse.de> <1132125965.3656.15.camel@localhost.localdomain> <20051116180655.GC6908@suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2483 Lines: 56 On Wed, 16 Nov 2005, Greg KH wrote: > On Wed, Nov 16, 2005 at 02:26:04AM -0500, Adam Belay wrote: > > On Tue, 2005-11-15 at 22:31 -0800, Greg KH wrote: > > > On Tue, Nov 15, 2005 at 10:31:42PM -0500, Adam Belay wrote: > > > > This patch makes some improvements to pci_save_state and > > > > pci_restore_state. Instead of saving and restoring all standard > > > > registers (even read-only ones), it only restores necessary registers. > > > > Also, the command register is handled more carefully. Let me know if > > > > I'm missing anything important. > > > > > > > > > > > > --- a/drivers/pci/pm.c 2005-11-13 20:32:24.000000000 -0500 > > > > +++ b/drivers/pci/pm.c 2005-11-13 20:29:32.000000000 -0500 > > > > @@ -53,10 +53,13 @@ > > > > */ > > > > int pci_save_state(struct pci_dev *dev) > > > > { > > > > - int i; > > > > - /* XXX: 100% dword access ok here? */ > > > > - for (i = 0; i < 16; i++) > > > > - pci_read_config_dword(dev, i * 4,&dev->saved_config_space[i]); > > > > + struct pci_dev_config * conf = &dev->saved_config; > > > > + > > > > + pci_read_config_word(dev, PCI_COMMAND, &conf->command); > > > > + pci_read_config_byte(dev, PCI_CACHE_LINE_SIZE, &conf->cacheline_size); > > > > + pci_read_config_byte(dev, PCI_LATENCY_TIMER, &conf->latency_timer); > > > > + pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &conf->interrupt_line); > > > > > > Why are we saving and restoring smaller ammounts of config space now? > > > > After looking at the spec, it seems that most of the registers we were > > restoring were read-only and couldn't possibly need to be restored. > > Also, the PCI PM spec suggests that only a subset of the registers > > should be restored. Finally, things like BIST should probably never be > > touched. > > Ok, but be aware that this _might_ cause problems for some cards/drivers > that were relying on the old way... As long as you don't mind me > assigning those bugs to you, I don't have a problem with this :) If any drivers have bugs in that area, then they most likely only worked by accident in the first place. The confg space is mostly read-only anyway, and there could be things we don't want to blindly overwrite. If any drivers need more, they should save it themselves. Pat - 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/