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86fd887b7f
Commit 20cde69402 ("x86, ia64: Move EFI_FB vga_default_device()
initialization to pci_vga_fixup()") moved boot video device detection from
efifb to x86 and ia64 pci/fixup.c.
For dual-GPU Apple computers above change represents a regression as code
in efifb did forcefully override vga_default_device while the merge did not
(vgaarb happens prior to PCI fixup).
To improve on initial device selection by vgaarb (it cannot know if PCI
device not behind bridges see/decode legacy VGA I/O or not), move the
screen_info based check from pci_video_fixup() to vgaarb's init function and
use it to refine/override decision taken while adding the individual PCI
VGA devices. This way PCI fixup has no reason to adjust vga_default_device
anymore but can depend on its value for flagging shadowed VBIOS.
This has the nice benefit of removing duplicated code but does introduce a
#if defined() block in vgaarb. Not all architectures have screen_info and
would cause compile to fail without it.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=84461
Reported-and-Tested-By: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Matthew Garrett <matthew.garrett@nebula.com>
CC: stable@vger.kernel.org # v3.5+
70 lines
2.2 KiB
C
70 lines
2.2 KiB
C
/*
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* Exceptions for specific devices. Usually work-arounds for fatal design flaws.
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* Derived from fixup.c of i386 tree.
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*/
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#include <linux/pci.h>
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#include <linux/init.h>
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#include <linux/vgaarb.h>
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#include <linux/screen_info.h>
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#include <asm/machvec.h>
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/*
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* Fixup to mark boot BIOS video selected by BIOS before it changes
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*
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* From information provided by "Jon Smirl" <jonsmirl@gmail.com>
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*
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* The standard boot ROM sequence for an x86 machine uses the BIOS
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* to select an initial video card for boot display. This boot video
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* card will have it's BIOS copied to C0000 in system RAM.
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* IORESOURCE_ROM_SHADOW is used to associate the boot video
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* card with this copy. On laptops this copy has to be used since
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* the main ROM may be compressed or combined with another image.
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* See pci_map_rom() for use of this flag. Before marking the device
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* with IORESOURCE_ROM_SHADOW check if a vga_default_device is already set
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* by either arch cde or vga-arbitration, if so only apply the fixup to this
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* already determined primary video card.
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*/
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static void pci_fixup_video(struct pci_dev *pdev)
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{
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struct pci_dev *bridge;
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struct pci_bus *bus;
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u16 config;
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if ((strcmp(ia64_platform_name, "dig") != 0)
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&& (strcmp(ia64_platform_name, "hpzx1") != 0))
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return;
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/* Maybe, this machine supports legacy memory map. */
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/* Is VGA routed to us? */
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bus = pdev->bus;
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while (bus) {
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bridge = bus->self;
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/*
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* From information provided by
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* "David Miller" <davem@davemloft.net>
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* The bridge control register is valid for PCI header
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* type BRIDGE, or CARDBUS. Host to PCI controllers use
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* PCI header type NORMAL.
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*/
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if (bridge && (pci_is_bridge(bridge))) {
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pci_read_config_word(bridge, PCI_BRIDGE_CONTROL,
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&config);
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if (!(config & PCI_BRIDGE_CTL_VGA))
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return;
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}
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bus = bus->parent;
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}
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if (!vga_default_device() || pdev == vga_default_device()) {
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pci_read_config_word(pdev, PCI_COMMAND, &config);
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if (config & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
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pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
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dev_printk(KERN_DEBUG, &pdev->dev, "Video device with shadowed ROM\n");
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}
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}
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}
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DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_ANY_ID, PCI_ANY_ID,
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PCI_CLASS_DISPLAY_VGA, 8, pci_fixup_video);
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