Re: [Bugfix v5] x86/PCI/ACPI: Fix regression caused by commit 63f1789ec716

[Ingo Molnar <mingo@kernel.org>]

* Jiang Liu <jiang.liu@linux.intel.com> wrote:

> Before commit 593669c2ac0f("Use common ACPI resource interfaces to
> simplify implementation"), arch/x86/pci/acpi.c applies following

s/applies following
 /applied the following

> rules when parsing ACPI resources for PCI host bridge:
> 1) Ignore IO port resources defined by acpi_resource_io and
>    acpi_resource_fixed_io, which should be used to define resource
>    for PCI device instead of PCI bridge.
> 2) Accept IOMEM resource defined by acpi_resource_memory24,
>    acpi_resource_memory32 and acpi_resource_fixed_memory32.
>    These IOMEM resources are accepted to workaround some BIOS issue,

s/workaround
 /work around

It's a verb, not a noun.

>    though they should be ignored. For example, PC Engines APU.1C

Please put the platform name into quotes to make it more clearly stand 
apart from the rest of the text.

>    platform defines PCI host bridge IOMEM resources as:
>                 Memory32Fixed (ReadOnly,
>                     0x000A0000,         // Address Base
>                     0x00020000,         // Address Length
>                     )
>                 Memory32Fixed (ReadOnly,
>                     0x00000000,         // Address Base
>                     0x00000000,         // Address Length
>                     _Y00)
> 3) Accept all IO port and IOMEM resources defined by
>    acpi_resource_address{16,32,64,extended64}, no matter it's marked as
>    ACPI_CONSUMER or ACPI_PRODUCER.

s/no matter it's marked
 /regardless of whether it's marked

> Commit 593669c2ac0f("Use common ACPI resource interfaces to
> simplify implementation") accept all IO port and IOMEM resources

s/accept
 /started accepting

> defined by acpi_resource_io, acpi_resource_fixed_io,
> acpi_resource_memory24, acpi_resource_memory32,
> acpi_resource_fixed_memory32 and
> acpi_resource_address{16,32,64,extended64}, which causes IO port
> resources consumed by host bridge itself are listed in to host bridge
> resource list.

this latter part of the sentence does not parse. Did you want to 
write:

  acpi_resource_address{16,32,64,extended64}, which causes IO port
  resources consumed by the host bridge itself to be listed in the
  host bridge resource list.

?

> Then commit 63f1789ec716("Ignore resources consumed by host bridge
> itself") ignores resources consumed by host bridge itself by checking

s/ignores
 /started ignoring

s/by host bridge
 /by the host bridge

> IORESOURCE_WINDOW flag, which accidently removed the workaround in 2)
> above for BIOS bug .

s/for BIOS bug .
 /for the BIOS bug.

> So revert to the behavior before v3.19 to fix the regression.
> 
> Sample ACPI table are archived at:
> https://bugzilla.kernel.org/show_bug.cgi?id=94221
> 
> Fixes: 63f1789ec716("Ignore resources consumed by host bridge itself")
> Reported-and-Tested-by: Bernhard Thaler <bernhard.thaler@wvnet.at>
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> ---
>  arch/x86/pci/acpi.c     |   25 ++++++++++++++++++++++---
>  drivers/acpi/resource.c |    6 +++++-
>  2 files changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
> index e4695985f9de..fc2da98985c3 100644
> --- a/arch/x86/pci/acpi.c
> +++ b/arch/x86/pci/acpi.c
> @@ -332,12 +332,32 @@ static void probe_pci_root_info(struct pci_root_info *info,
>  {
>  	int ret;
>  	struct resource_entry *entry, *tmp;
> +	unsigned long res_flags;
>  
>  	sprintf(info->name, "PCI Bus %04x:%02x", domain, busnum);
>  	info->bridge = device;
> +
> +	/*
> +	 * An IO or MMIO resource assigned to PCI host bridge may be consumed

s/to PCI host bridge
 /to a PCI host bridge

> +	 * by the host bridge itself or available to its child bus/devices.
> +	 * On x86 and IA64 platforms, all IO and MMIO resources are assumed to
> +	 * be available to child bus/devices except one special case:
> +	 *	IO port [0xCF8-0xCFF] is consumed by host bridge itself to

s/by host bridge
 /by the host bridge

> +	 *	access PCI configuration space.
> +	 *
> +	 * Due to lack of specification to define resources consumed by host
> +	 * bridge itself, all IO port resources defined by acpi_resource_io

s/by host bridge
 /by the host bridge

> +	 * and acpi_resource_fixed_io are ignored to filter out IO
> +	 * port[0xCF8-0xCFF]. Seems this solution works with all BIOSes, though
> +	 * it's not perfect.
> +	 *
> +	 * Another possible solution is to explicitly filter out IO

s/is to
 /would be to

> +	 * port[0xCF8-0xCFF].
> +	 */
> +	res_flags = IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_IO_FIXED;
>  	ret = acpi_dev_get_resources(device, list,
>  				     acpi_dev_filter_resource_type_cb,
> -				     (void *)(IORESOURCE_IO | IORESOURCE_MEM));
> +				     (void *)res_flags);
>  	if (ret < 0)
>  		dev_warn(&device->dev,
>  			 "failed to parse _CRS method, error code %d\n", ret);
> @@ -346,8 +366,7 @@ 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..79b6d3b5ffd2 100644
> --- a/drivers/acpi/resource.c
> +++ b/drivers/acpi/resource.c
> @@ -575,6 +575,9 @@ EXPORT_SYMBOL_GPL(acpi_dev_get_resources);
>   *
>   * This is a hepler function to support acpi_dev_get_resources(), which filters
>   * ACPI resource objects according to resource types.
> + *
> + * Flag IORESOURCE_IO_FIXED is used to opt out io and fixed_io resource

s/Flag IORESOURCE_IO_FIXED is used to opt out io and fixed_io resource
  The IORESOURCE_IO_FIXED flag is used to opt out IO and FIXED_IO resource

> + * descriptors for ACPI host bridges on x86 and IA64 platforms.
>   */
>  int acpi_dev_filter_resource_type(struct acpi_resource *ares,
>  				  unsigned long types)
> @@ -589,7 +592,8 @@ int acpi_dev_filter_resource_type(struct acpi_resource *ares,
>  		break;
>  	case ACPI_RESOURCE_TYPE_IO:
>  	case ACPI_RESOURCE_TYPE_FIXED_IO:
> -		type = IORESOURCE_IO;
> +		if ((types & IORESOURCE_IO_FIXED) == 0)
> +			type = IORESOURCE_IO;
>  		break;
>  	case ACPI_RESOURCE_TYPE_IRQ:
>  	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
> -- 
> 1.7.10.4
> 

Thanks,

	Ingo