On Mon, Mar 23, 2015 at 03:22:14PM +0800, Jiang Liu wrote:
> Commit 63f1789ec716("Ignore resources consumed by host bridge itself")
> tries to ignore resources consumed by PCI host bridge itself by
> checking IORESOURCE_WINDOW flag, which causes regression on some
> platforms.
"Do. Or do not. There is no try."
[http://www.starwars.com/video/do-or-do-not]
That commit doesn't *try* to do something. It *does* something. Just
explain what it does and what's wrong with what it does.
> For example, PC Engines APU.1C platform defines PCI MMIO resources with
> ACPI Memory32Fixed operator as below:
> Name (CRES, ResourceTemplate ()
> {
> ...
> WordIO (ResourceProducer, MinFixed, MaxFixed, PosDecode,
> 0x0000, // Granularity
> 0x0D00, // Range Minimum
> 0xFFFF, // Range Maximum
> 0x0000, // Translation Offset
> 0xF300, // Length
> ,, , TypeStatic)
> Memory32Fixed (ReadOnly,
> 0x000A0000, // Address Base
> 0x00020000, // Address Length
> )
> Memory32Fixed (ReadOnly,
> 0x00000000, // Address Base
> 0x00000000, // Address Length
> _Y00)
> })
>
> Memory32Fixed operator doesn't support concept of "producer/consumer"
> and it will be treated as "consumer" by the ACPI resource parsing
> interface, thus cause regression. So the fix is only to check
> "producer/consumer" flag for resources having "producer/consumer" flag.
Apparently the problem is with the Memory32Fixed resources above; it sounds
like we ignore them after 63f1789ec716? I don't quite understand how this
fix works. acpi_dev_filter_resource_type() has cases for both
ACPI_RESOURCE_TYPE_FIXED_MEMORY32 and ACPI_RESOURCE_TYPE_ADDRESSxx, but
this patch only touches the latter, not the
ACPI_RESOURCE_TYPE_FIXED_MEMORY32 case.
Is it even legal to use Memory32Fixed for a bridge window? Is this just a
BIOS bug? If so, how do we know this workaround won't break something
else for BIOSes that use Memory32Fixed correctly?
Should this be a BIOS-specific quirk?
Incidentally, I also noticed this change:
--- dmesg_3.18.0-rc5.txt 2015-03-23 10:49:25.064682404 -0500
+++ dmesg_4.0.0-rc4.txt 2015-03-23 10:49:29.276630002 -0500
-ACPI: PCI Interrupt Link [INTA] (IRQs 3 4 5 7 10 11 12 15) *0, disabled.
+ACPI: PCI Interrupt Link [INTA] (IRQs 3 4 5 7 10 11 12 15) *0
Is it intentional that INTA was previously reported as disabled but isn't
any more?
And there's also this:
acpi PNP0A03:00: [Firmware Bug]: no secondary bus range in _CRS
That isn't a change (it was there in 3.18, too), but that really is a
pretty basic BIOS bug and indicates that we shouldn't be too surprised if
it has other bugs.
> Another possible fix is to only ignore IO resource consumed by host
> bridge and keep IOMEM resource consumed by host bridge, please refer to:
> http://www.spinics.net/lists/linux-pci/msg39706.html
It'd be nice to have Bernhard's logs archived somewhere and referenced
here. This seems like a dusty corner of the code that might have to be
revisited someday.
> Fixes: 63f1789ec716("Ignore resources consumed by host bridge itself")
> Reported-by: Bernhard Thaler <bernhard.thaler@xxxxxxxx>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> ---
> Hi Bernhard,
> Could you please also help to test whether this patch works for
> you too?
> Thanks!
> Gerry
> ---
> arch/x86/pci/acpi.c | 5 ++---
> drivers/acpi/resource.c | 3 +++
> 2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
> index e4695985f9de..8c4b1201f340 100644
> --- a/arch/x86/pci/acpi.c
> +++ b/arch/x86/pci/acpi.c
> @@ -337,7 +337,7 @@ static void probe_pci_root_info(struct pci_root_info *info,
> info->bridge = device;
> ret = acpi_dev_get_resources(device, list,
> acpi_dev_filter_resource_type_cb,
> - (void *)(IORESOURCE_IO | IORESOURCE_MEM));
> + (void *)(IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_WINDOW));
Tangent: I'm disappointed that ia64 didn't get reworked to track the x86
code here. Is that coming soon?
> if (ret < 0)
> dev_warn(&device->dev,
> "failed to parse _CRS method, error code %d\n", ret);
> @@ -346,8 +346,7 @@ static void probe_pci_root_info(struct pci_root_info *info,
> "no IO and memory resources present in _CRS\n");
> else
> resource_list_for_each_entry_safe(entry, tmp, list) {
> - if ((entry->res->flags & IORESOURCE_WINDOW) == 0 ||
> - (entry->res->flags & IORESOURCE_DISABLED))
> + if (entry->res->flags & IORESOURCE_DISABLED)
> resource_list_destroy_entry(entry);
> else
> entry->res->name = info->name;
> diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
> index 5589a6e2a023..b0d3f2ceef06 100644
> --- a/drivers/acpi/resource.c
> +++ b/drivers/acpi/resource.c
> @@ -606,6 +606,9 @@ int acpi_dev_filter_resource_type(struct acpi_resource *ares,
> case ACPI_RESOURCE_TYPE_ADDRESS32:
> case ACPI_RESOURCE_TYPE_ADDRESS64:
> case ACPI_RESOURCE_TYPE_EXTENDED_ADDRESS64:
> + if (((types & IORESOURCE_WINDOW) == 0) ^
> + (ares->data.address.producer_consumer == ACPI_CONSUMER))
> + break;
> if (ares->data.address.resource_type == ACPI_MEMORY_RANGE)
> type = IORESOURCE_MEM;
> else if (ares->data.address.resource_type == ACPI_IO_RANGE)
> --
> 1.7.10.4
>
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