[PATCH] pciehp: reduce dependence on ACPI

Reduce the PCI Express hotplug driver's dependence on ACPI.
We don't walk the acpi namespace anymore to build a list of
bridges and devices. We go to ACPI only to run the _OSC or
_OSHP methods to transition control of hotplug hardware from
system BIOS to the hotplug driver, and to run the _HPP
method to get hotplug device parameters like cache line size,
latency timer and SERR/PERR enable from BIOS.

Note that one of the side effects of this patch is that pciehp
does not automatically enable the hot-added device or its DMA
bus mastering capability now. It expects the device driver to
do that. This may break some drivers and we will have to fix
them as they are reported.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 7a0e27f0e063..ef79ca1f38da 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -1470,6 +1470,10 @@ int pcie_init(struct controller * ctrl,
         }
         dbg("%s: SLOT_STATUS offset %x writes slot_status %x\n", __FUNCTION__, SLOT_STATUS(ctrl->cap_base), temp_word);
         
+        rc = get_hp_hw_control_from_firmware(ctrl->pci_dev);
+        if (rc)
+                goto abort_free_ctlr;
+
         /*  Add this HPC instance into the HPC list */
         spin_lock(&list_lock);
         if (php_ctlr_list_head == 0) {