Commit 0509ad5e authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by Linus Torvalds
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PNP: disable PNP motherboard resources that overlap PCI BARs 

Some BIOSes have PNP motherboard devices with resources that
partially overlap PCI BARs.  The PNP system driver claims these
motherboard resources, which prevents the normal PCI driver from
requesting them later.

This patch disables the PNP resources that conflict with PCI BARs
so they won't be claimed by the PNP system driver.

Of course, this only works if PCI devices have already been enumerated.
Currently this is the case because PCI devices are discovered before
any PNP init via this path:

    acpi_pci_root_init() -> acpi_pci_root_add() -> pci_acpi_scan_root() ->
	pci_scan_bus_parented() -> pci_scan_child_bus() -> ...

Avuton Olrich tested this and confirmed that it fixes his ALSA sound
card (see http://lkml.org/lkml/2008/1/27/168).

References:
    https://bugzilla.redhat.com/show_bug.cgi?id=280641
    https://bugzilla.redhat.com/show_bug.cgi?id=313491
    http://lkml.org/lkml/2008/1/9/449
    http://thread.gmane.org/gmane.linux.acpi.devel/27312
    http://lkml.org/lkml/2008/1/27/168



Signed-off-by: default avatarBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e0aca233

drivers/pnp/quirks.c

+73 −0
Original line number Diff line number Diff line
@@ -108,6 +108,77 @@ static void quirk_sb16audio_resources(struct pnp_dev *dev) 
		       "pnp: SB audio device quirk - increasing port range\n");

}





#include <linux/pci.h>



static void quirk_system_pci_resources(struct pnp_dev *dev)

{

	struct pci_dev *pdev = NULL;

	resource_size_t pnp_start, pnp_end, pci_start, pci_end;

	int i, j;



	/*

	 * Some BIOSes have PNP motherboard devices with resources that

	 * partially overlap PCI BARs.  The PNP system driver claims these

	 * motherboard resources, which prevents the normal PCI driver from

	 * requesting them later.

	 *

	 * This patch disables the PNP resources that conflict with PCI BARs

	 * so they won't be claimed by the PNP system driver.

	 */

	for_each_pci_dev(pdev) {

		for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {

			if (!(pci_resource_flags(pdev, i) & IORESOURCE_MEM) ||

			    pci_resource_len(pdev, i) == 0)

				continue;



			pci_start = pci_resource_start(pdev, i);

			pci_end = pci_resource_end(pdev, i);

			for (j = 0; j < PNP_MAX_MEM; j++) {

				if (!pnp_mem_valid(dev, j) ||

				    pnp_mem_len(dev, j) == 0)

					continue;



				pnp_start = pnp_mem_start(dev, j);

				pnp_end = pnp_mem_end(dev, j);



				/*

				 * If the PNP region doesn't overlap the PCI

				 * region at all, there's no problem.

				 */

				if (pnp_end < pci_start || pnp_start > pci_end)

					continue;



				/*

				 * If the PNP region completely encloses (or is

				 * at least as large as) the PCI region, that's

				 * also OK.  For example, this happens when the

				 * PNP device describes a bridge with PCI

				 * behind it.

				 */

				if (pnp_start <= pci_start &&

				    pnp_end >= pci_end)

					continue;



				/*

				 * Otherwise, the PNP region overlaps *part* of

				 * the PCI region, and that might prevent a PCI

				 * driver from requesting its resources.

				 */

				dev_warn(&dev->dev, "mem resource "

					"(0x%llx-0x%llx) overlaps %s BAR %d "

					"(0x%llx-0x%llx), disabling\n",

					(unsigned long long) pnp_start,

					(unsigned long long) pnp_end,

					pci_name(pdev), i,

					(unsigned long long) pci_start,

					(unsigned long long) pci_end);

				pnp_mem_flags(dev, j) = 0;

			}

		}

	}

}



/*

 *  PnP Quirks

 *  Cards or devices that need some tweaking due to incomplete resource info
@@ -128,6 +199,8 @@ static struct pnp_fixup pnp_fixups[] = { 
	{"CTL0043", quirk_sb16audio_resources},

	{"CTL0044", quirk_sb16audio_resources},

	{"CTL0045", quirk_sb16audio_resources},

	{"PNP0c01", quirk_system_pci_resources},

	{"PNP0c02", quirk_system_pci_resources},

	{""}

};

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