On 01/19/2010 02:52 PM, Bjorn Helgaas wrote: > On Tuesday 19 January 2010 12:57:39 pm Yinghai Lu wrote: >> On 01/19/2010 11:42 AM, Jeff Garrett wrote: >>> On Fri, Jan 15, 2010 at 10:14:17AM -0800, Jesse Barnes wrote: >>>> On Thu, 14 Jan 2010 16:39:13 -0800 >>>> Yinghai Lu <yinghai@xxxxxxxxxx> wrote: >>>> >>>>> On 01/14/2010 03:49 PM, Bjorn Helgaas wrote: >>>>>> On Thursday 14 January 2010 04:38:08 pm Yinghai Lu wrote: >>>>>>> On 01/14/2010 03:09 PM, Bjorn Helgaas wrote: >>>>>>>> On Thursday 14 January 2010 03:46:35 pm Yinghai Lu wrote: >>>>>>>>> >>>>>>>>> Bjorn pointed out we need to remove mmconf range >>>>>>>>> >>>>>>>>> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> >>>>>>>>> >>>>>>>>> --- >>> ... >>>>>>>> >>>>>>>> This can't be right, can it? Let's say the kernel was built with >>>>>>>> CONFIG_PCI_MMCONFIG turned off, or the user used "pci=nommconf", >>>>>>>> or the kernel decides not to use MMCONFIG for some other reason. >>>>>>>> >>>>>>>> In that case, the hardware may still be configured to support >>>>>>>> MMCONFIG, but the pci_mmcfg_list will be empty, so your code will >>>>>>>> leave the window alone. We might assign some of that MMCONFIG >>>>>>>> space to a device, but the hardware will route it to MMCONFIG, >>>>>>>> not to the device. >>>>>>> >>>>>>> so if there is mmconf specified, we just skip the whole function? >>>>>> >>>>>> No, I'm saying that intel-bus.c must ALWAYS remove the MMCONFIG >>>>>> region from the host bridge apertures, even if Linux isn't using >>>>>> MMCONFIG. >>>>>> >>>>>> That means intel-bus.c has to be smart enough to figure out on its >>>>>> own what the MMCONFIG area is. It can't depend on mmconfig-shared.c >>>>>> to do it, because mmconfig-shared.c might not be there. >>>>> >>>>> that seems go too far away... >>>>> >>>>> Subject: [PATCH -v2] x86/pci: intel ioh need to subtrac mmconf range >>>>> >>>>> Bjorn pointed out we need to remove mmconf range >>>>> >>>>> -v2: if mmconf is not there, get out early. >>>>> >>>>> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx> >>>>> >>>>> --- >>> ... >>>> >>>> This goes against the real intent of intel_bus.c doesn't it? When we >>>> first added it, the thought was that it would be a purely native way of >>>> getting at bridge window information and not rely on firmware. If >>>> you're going to make it dependent on MMCONFIG now, why not trust other >>>> firmware tables as well, like _CRS? >>>> >>>> The MMCONFIG ranges are pretty easy to get at, the public docs have >>>> info about the registers that control the MMCONFIG decode ranges, so >>>> you should be able to read them out and add them to this file, >>>> preserving the original intent. >>> >>> I did attempt a bisection last week, but my pared down config kept >>> hitting a sysfs_create_file panic. I didn't succeed. > > I don't think there's any need to bisect this; sorry I didn't > mention this earlier. > > 2.6.32 didn't include intel-bus.c, so the kernel just assumed that > all non-RAM addresses got routed to the PCI bus. This would have > included the [mem 0xd0000000-0xdfffffff] used by your Radeon device, > which explains why it would work there. > > After 2.6.32, we added intel-bus.c, which reads some of the host > bridge aperture information from the chipset. This is apparently > missing something, because intel-bus.c didn't find that region, > so Linux thought the Radeon resource was wrong and disabled it, > which broke it. > >>> Should I try the v2 patch above? What tree is it against? >> >> maybe later with -tip tree + pci/linux-next. > > Yinghai, did you figure out how to discover the [mem 0xd0000000-0xdfffffff] > region in intel-bus.c? Jeff's video isn't going to work without that. > didn't get info from vendor yet. looks there is some bit that will enable those register, otherwise those register should not be used. YH -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
