Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755413Ab3COPO2 (ORCPT ); Fri, 15 Mar 2013 11:14:28 -0400 Received: from cantor2.suse.de ([195.135.220.15]:39365 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754556Ab3COPO0 (ORCPT ); Fri, 15 Mar 2013 11:14:26 -0400 Date: Fri, 15 Mar 2013 16:14:17 +0100 (CET) From: Jiri Kosina To: Harald Arnesen Cc: Kernel development list , "Rafael J. Wysocki" , Peter Hurley , Alan Stern , Thomas Meyer , Shawn Starr , USB list , linux-acpi@vger.kernel.org, Bjorn Helgaas , linux-pci@vger.kernel.org, Yinghai Lu , Daniel Vetter , Imre Deak , Daniel Kurtz , dri-devel@lists.freedesktop.org Subject: Re: [3.9-rc1] irq 16: nobody cared (was [3.9-rc1] very poor interrupt responses) In-Reply-To: Message-ID: References: <1460519.ejNFI1DrGk@vostro.rjw.lan> <1363280764.26318.4.camel@thor.lan> <5657408.cYX6iimiA4@vostro.rjw.lan> <5142E7F0.4020002@gmail.com> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1859 Lines: 49 On Fri, 15 Mar 2013, Jiri Kosina wrote: > > I have the same problem on my Lenovo T500. I think the graphics card is > > involved. > > > > This laptop has "hybrid graphics" - one Intel GMA 4500MHD and one ATI > > Mobility Radeon HD 3650. When I boot with the Intel card, I get "irq 16: > > nobody cared" during boot, not when I boot with the ATI card. > > Confirming this. After a lot of hassle, I have bisected this reliably to > > commit 28c70f162a315bdcfbe0bf940a740ef8bfb918d6 > Author: Daniel Vetter > Date: Sat Dec 1 13:53:45 2012 +0100 > > drm/i915: use the gmbus irq for waits > > Adding Daniel, Imre and Daniel to CC while I will try to figure out what's > happening in parallel. > > Attaching dmesg.txt from the machine with 28c70f162a as head, with > drm.debug=0xe. Just a datapoint -- I have put a trivial debugging patch in place, and it reveals that "nobody cared" for irq 16 happens long after last I915_WRITE(GMBUS4 + reg_offset, 0); has been performed in gmbus_wait_hw_status(). On the other hand, if I comment out both GMBUS4 register offset writes in gmbus_wait_hw_status(), then it of course falls back to GPIO bit-banging, but the "nobody cared" for irq 16 is gone. So it seems like something gets severely confused by the I915_WRITE to GMBUS4 + reg_offset. So far this seems to have been reported solely on Lenovos as far as I can see (although a completely different types), so it might be some platform-specific quirk? Honestly, I still don't understand how all the GMBUS stuff relates to IRQ 16 at all. -- Jiri Kosina SUSE Labs -- 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/