From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932152Ab0KPTrP (ORCPT ); Tue, 16 Nov 2010 14:47:15 -0500 Received: from ist.d-labs.de ([213.239.218.44]:48190 "EHLO mx01.d-labs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758538Ab0KPTrO (ORCPT ); Tue, 16 Nov 2010 14:47:14 -0500 Date: Tue, 16 Nov 2010 20:46:45 +0100 From: Florian Mickler To: Jesse Barnes Cc: "Rafael J. Wysocki" , Dave Airlie , Thomas Gleixner , LKML , Ingo Molnar , Keith Packard Subject: Re: "do_IRQ: 0.89 No irq handler for vector (irq -1)" Message-ID: <20101116204645.2c105e9b@schatten.dmk.lab> In-Reply-To: <20101012124938.47170457@jbarnes-desktop> References: <20101011154826.440b4990@jbarnes-desktop> <20101011164014.5a11ee48@jbarnes-desktop> <201010122101.17812.rjw@sisk.pl> <20101012124938.47170457@jbarnes-desktop> X-Mailer: Claws Mail 3.7.6cvs31 (GTK+ 2.20.1; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 12 Oct 2010 12:49:38 -0700 Jesse Barnes wrote: > On Tue, 12 Oct 2010 21:01:17 +0200 > "Rafael J. Wysocki" wrote: > > > On Tuesday, October 12, 2010, Jesse Barnes wrote: > > > On Mon, 11 Oct 2010 15:48:26 -0700 > > > Jesse Barnes wrote: > > > > > > > On Fri, 8 Oct 2010 21:46:50 +1000 > > > > Dave Airlie wrote: > > > > > Not sure how best to fix, I can workaround by calling > > > > > pci_set_power_state(PCI_D0) in the drm drivers, but I sorta thing the > > > > > PCI layer should take care of this. > > > > > > > > So I think we *should* be able to call pci_disable_device at remove > > > > time. But as you say, some platforms may not correctly re-route VGA > > > > space to an existing device or disable it properly when we do that. > > > > AFAICT x86 will be ok here though (seems to work ok locally too). > > > > > > Just tested this some more, and I think it's the right thing to do in > > > the KMS case at least. When we load a KMS driver it takes over the gfx > > > device and nothing can assume anything about VGA state unless using the > > > VGA arbiter. So calling pci_disable_device() in the shutdown path of a > > > KMS driver shouldn't make things any worse, and will work around this > > > issue. > > > > > > Doing so in the non-KMS case violates some PC assumptions though, in > > > that things like vgacon and the BIOS will assume VGA memory is still > > > around, which on some platforms pci_disable_device() may affect (I only > > > checked the x86 implementation). > > > > > > > That said, it seems like we should update the current device state at > > > > load time as well, once we've matched the driver it seems like there > > > > should be no harm. > > > > > > > > Rafael, what do you think? Would having the correct power state at > > > > load time cause any trouble with other PM code? I know we've had > > > > issues with setting it explicitly in the past... > > > > > > So we should probably make pci_enable_device pick up the current state > > > as well, instead of assuming it's unknown just because the enable count > > > was non-zero (which as Dave points out, can be affected by sysfs writes > > > too). > > > > > > The only downside I can think of there is that if the device is already > > > enabled, we generally have to assume another driver owns it, and who > > > knows if the device is actually alive enough to read the current state > > > from. But I think we handle those errors ok too, so pulling it out > > > should be safe. > > > > I remember trying to do something like this and it didn't play well with the > > initialization. Still, I didn't do that in pci_enable_device(), so I can't say > > for sure at the moment. I _think_ it will be fine, though. > > Seems to work ok for the buggy i915 reload case. But looking at it > again, I really don't like two things: > 1) doing just the set_power_state seems wrong, what about the rest of > enable? > 2) allowing nested enables at all > > I know sysfs currently allows us to bump the enable count to arbitrary > levels, but that's easy to fix; we can just check pci_is_enabled() > before calling enable_device in the sysfs store routine. > > If we did that, we could warn when pci_enable_device is called in a > nested way, which is generally a bug (two drivers trying to take over a > device?). > > I don't think I buy that VGA is special anyway, at least not for KMS > enabled kernels, where vgacon and the BIOS can't assume anything about > graphics state anymore. More generally, I don't think BIOSes have been > able to assume anything about the current graphics state since Windows > 3.1, when most platforms stopped using BIOS calls and/or VGA regs for > mode setting. > > Thoughts? > does this need to go to 2.6.36.y? (is it already on it's way?) commit 97c145f7c87453cec90e91238fba5fe2c1561b32 Author: Jesse Barnes Date: Fri Nov 5 15:16:36 2010 -0400 PCI: read current power state at enable time