From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757279Ab0GNSMP (ORCPT ); Wed, 14 Jul 2010 14:12:15 -0400 Received: from tx2ehsobe004.messaging.microsoft.com ([65.55.88.14]:48173 "EHLO TX2EHSOBE008.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756779Ab0GNSMN convert rfc822-to-8bit (ORCPT ); Wed, 14 Jul 2010 14:12:13 -0400 X-SpamScore: -45 X-BigFish: VPS-45(zz1432N98dN179dN140eM9371P15bfMzz1202hzz15d4Rz32i2a8h43h61h) X-Spam-TCS-SCL: 0:0 X-WSS-ID: 0L5K7W4-01-DL0-02 X-M-MSG: Date: Wed, 14 Jul 2010 20:11:52 +0200 From: Borislav Petkov To: Linus Torvalds CC: Stephan Wolf , , , Andreas Herrmann Subject: Re: [PATCH] enable readback to get HPET working on ATI SB4x00, kernel 2.6.35_rc5 Message-ID: <20100714181152.GB15651@aftab> References: <4C3DDDFF.5040302@letzte-bankreihe.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Content-Transfer-Encoding: 8BIT X-Reverse-DNS: unknown Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds Date: Wed, Jul 14, 2010 at 09:13:39AM -0700 > On Wed, Jul 14, 2010 at 8:55 AM, Stephan Wolf > wrote: > > > >  After commit 30a564be9d9554c168a654eddc2165869cc0d7bf "x86, hpet: Restrict > > read back to affected ATI chipsets" hpet did not work anymore on HP nx6325. > > The machine hangs on booting until a keystroke was taken. After a short time > > machine hangs again until next keystroke. Applying the following patch > > solves the issue for me. > > Ok, this makes sense. Bugs in the ATI chipset is why > 'hpet_readback_cmp' exists in the first place. HOWEVER, clearly that > commit changed it to be about too few ATI chipsets. > > So right now, for > > - PCI_DEVICE_ID_ATI_SBX00_SMBUS: > force disable HPET MSI > force HPET readback > > - PCI_DEVICE_ID_ATI_IXP400_SMBU > force-enable HPET > ...and than your patch makes it force HPET readback > > but that doesn't actually make much sense in the bigger picture, > because there are other ATI chipsets that are related and presumably > also affected. What about IXP[23]00_SMBUS? And what about the IXP7 > series (SBX00 is IXP6, afaik)? Right, so the original commit introducing the readback did it for all ATI chipsets: 72d43d9bc9210d24d09202eaf219eac09e17b339. We've been running fine with it so far modulo the Intel ICH9 issue. I'll try to find out which chipsets are actually affected but in the meantime we might want to do a temporary fix by enabling the readback back(!) on all ATI chipsets so that we don't uncover anymore bugs like the one above, hmmm? > And I added Andreas to the cc, maybe he knows what's up. He'll be back on Mo. -- Regards/Gruss, Boris. Advanced Micro Devices GmbH Einsteinring 24, 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632