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

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Monday, April 13, 2015 08:56:17 AM Ingo Molnar wrote:
> 
> * 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.

Agreed on this one an all of the points below.

> >    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:


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.