From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lin Ming Subject: Re: DMA doesn't work since "make ata port as parent device of scsi host" Date: Thu, 15 Mar 2012 16:19:58 +0800 Message-ID: <1331799598.3436.46.camel@minggr> References: <20120315014807.GA3051@alea.gnuu.de> <1331776741.3436.33.camel@minggr> <1331781968.3436.43.camel@minggr> <20120315074835.GA18295@alea.gnuu.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mga01.intel.com ([192.55.52.88]:42620 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756317Ab2COIUA (ORCPT ); Thu, 15 Mar 2012 04:20:00 -0400 In-Reply-To: <20120315074835.GA18295@alea.gnuu.de> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: =?ISO-8859-1?Q?J=F6rg?= Sommer Cc: Jeff Garzik , Tejun Heo , linux-ide@vger.kernel.org On Thu, 2012-03-15 at 08:48 +0100, J=C3=B6rg Sommer wrote: > Lin Ming hat am Thu 15. Mar, 11:26 (+0800) geschrieben: > > On Thu, 2012-03-15 at 09:59 +0800, Lin Ming wrote: > > > On Thu, 2012-03-15 at 02:48 +0100, J=C3=B6rg Sommer wrote: > > > > Hi, > > > >=20 > > > > I'm getting these messages in a KVM virtualized host and the ac= cess to > > > > the disks is very slow. Using libata.dma=3D0 suppresses the war= nings, but > > > > the disks are still slow. > > >=20 > > > Hi J=C3=B6rg, > > >=20 > > > Let me try to reproduce this issue first. > >=20 > > I tried below commands on x86_32, but can't reproduce it. > >=20 > > qemu-system-i386 -kernel /root/vmlinuz-3.3.0-rc7 -append "root=3D/d= ev/sda1 > > zcache" -hda /root/debian-32.img -hdb /root/data.img > >=20 > > Maybe because i386 uses different ata controller than ppc(ata_piix = vs > > pata-macio). > >=20 > > I'll try qemu-system-ppc. > >=20 > > Did you need to run some workload to trigger these warings? > > Or did you get these warnings right after booting the VM? >=20 > These warnings come up before =C2=BBINIT started=C2=AB. I don't have = to do > anything, just wait and see. >=20 > # truncate -s100M /mnt/data/new > # mke2fs -Fq /mnt/data/new > # mount -o loop /mnt/data/new /mnt/other > # cp --parents /bin/zsh-static /mnt/other/zsh > # umount /mnt/other > # qemu-system-ppc -enable-kvm -M mac99 -cpu G4 -k de -kernel /boot/vm= linuz-3.3.0-rc5-04520-g8d233c0 -append 'root=3D/dev/sda ro console=3Dtt= yPZ0 init=3D/zsh' -hda /mnt/data/new >=20 > I've uploaded my config and the kernel: > http://alioth.debian.org/~jo-guest/config-3.3.0-rc5-04520-g8d233c0 > http://alioth.debian.org/~jo-guest/vmlinuz-3.3.0-rc5-04520-g8d233c0 >=20 > You have to switch to the serial console (Ctrl-Alt-3 or with -nograph= ic > Ctrl-a c). All kernel messages arrive there. >=20 > > Would you please try to disable ata port runtime pm? > > You can disable it by, for example, >=20 > Is this also possible with a kernel parameter? It takes very long unt= il I > get a shell prompt. No, but you can try below debug patch to disable port runtime pm. diff --git a/drivers/ata/libata-transport.c b/drivers/ata/libata-transp= ort.c index 74aaee3..8def3fc 100644 --- a/drivers/ata/libata-transport.c +++ b/drivers/ata/libata-transport.c @@ -293,7 +293,6 @@ int ata_tport_add(struct device *parent, =20 device_enable_async_suspend(dev); pm_runtime_set_active(dev); - pm_runtime_enable(dev); =20 transport_add_device(dev); transport_configure_device(dev); >=20 > Bye, J=C3=B6rg.