ebff5fa9d5
This reverts commit 81b5c7bc8d.
Adding drm/i915 into the vga arbiter chain means that X (in a piece of
well-meant paranoia) will do a get/put on the vga decoding around
_every_ accel call down into the ddx. Which results in some nice
performance disasters [1]. This really breaks userspace, by disabling
DRI for everyone, and stops OpenGL from working, this isn't limited
to just the i915 but both the integrated and discrete GPUs on
multi-gpu systems, in other words this causes untold worlds of pain,
Ville tried to come up with a Great Hack to fiddle the required VGA
I/O ops behind everyone's back using stop_machine, but that didn't
really work out [2]. Given that we're fairly late in the -rc stage for
such games let's just revert this all.
One thing we might want to keep is to delay the disabling of the vga
decoding until the fbdev emulation and the fbcon screen is set up. If
we kill vga mem decoding beforehand fbcon can end up with a white
square in the top-left corner it tried to save from the vga memory for
a seamless transition. And we have bug reports on older platforms
which seem to match these symptoms.
But again that's something to play around with in -next.
References: [1] http://lists.x.org/archives/xorg-devel/2013-September/037763.html
References: [2] http://www.spinics.net/lists/intel-gfx/msg34062.html
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
251 lines
9.1 KiB
C
251 lines
9.1 KiB
C
/*
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* The VGA aribiter manages VGA space routing and VGA resource decode to
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* allow multiple VGA devices to be used in a system in a safe way.
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*
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* (C) Copyright 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
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* (C) Copyright 2007 Paulo R. Zanoni <przanoni@gmail.com>
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* (C) Copyright 2007, 2009 Tiago Vignatti <vignatti@freedesktop.org>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#ifndef LINUX_VGA_H
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#define LINUX_VGA_H
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#include <video/vga.h>
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/* Legacy VGA regions */
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#define VGA_RSRC_NONE 0x00
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#define VGA_RSRC_LEGACY_IO 0x01
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#define VGA_RSRC_LEGACY_MEM 0x02
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#define VGA_RSRC_LEGACY_MASK (VGA_RSRC_LEGACY_IO | VGA_RSRC_LEGACY_MEM)
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/* Non-legacy access */
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#define VGA_RSRC_NORMAL_IO 0x04
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#define VGA_RSRC_NORMAL_MEM 0x08
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/* Passing that instead of a pci_dev to use the system "default"
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* device, that is the one used by vgacon. Archs will probably
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* have to provide their own vga_default_device();
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*/
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#define VGA_DEFAULT_DEVICE (NULL)
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struct pci_dev;
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/* For use by clients */
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/**
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* vga_set_legacy_decoding
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*
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* @pdev: pci device of the VGA card
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* @decodes: bit mask of what legacy regions the card decodes
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*
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* Indicates to the arbiter if the card decodes legacy VGA IOs,
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* legacy VGA Memory, both, or none. All cards default to both,
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* the card driver (fbdev for example) should tell the arbiter
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* if it has disabled legacy decoding, so the card can be left
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* out of the arbitration process (and can be safe to take
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* interrupts at any time.
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*/
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extern void vga_set_legacy_decoding(struct pci_dev *pdev,
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unsigned int decodes);
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/**
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* vga_get - acquire & locks VGA resources
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*
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* @pdev: pci device of the VGA card or NULL for the system default
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* @rsrc: bit mask of resources to acquire and lock
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* @interruptible: blocking should be interruptible by signals ?
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*
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* This function acquires VGA resources for the given
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* card and mark those resources locked. If the resource requested
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* are "normal" (and not legacy) resources, the arbiter will first check
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* whether the card is doing legacy decoding for that type of resource. If
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* yes, the lock is "converted" into a legacy resource lock.
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* The arbiter will first look for all VGA cards that might conflict
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* and disable their IOs and/or Memory access, including VGA forwarding
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* on P2P bridges if necessary, so that the requested resources can
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* be used. Then, the card is marked as locking these resources and
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* the IO and/or Memory accesse are enabled on the card (including
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* VGA forwarding on parent P2P bridges if any).
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* This function will block if some conflicting card is already locking
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* one of the required resources (or any resource on a different bus
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* segment, since P2P bridges don't differenciate VGA memory and IO
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* afaik). You can indicate whether this blocking should be interruptible
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* by a signal (for userland interface) or not.
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* Must not be called at interrupt time or in atomic context.
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* If the card already owns the resources, the function succeeds.
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* Nested calls are supported (a per-resource counter is maintained)
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*/
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#if defined(CONFIG_VGA_ARB)
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extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible);
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#else
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static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible) { return 0; }
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#endif
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/**
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* vga_get_interruptible
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*
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* Shortcut to vga_get
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*/
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static inline int vga_get_interruptible(struct pci_dev *pdev,
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unsigned int rsrc)
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{
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return vga_get(pdev, rsrc, 1);
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}
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/**
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* vga_get_uninterruptible
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*
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* Shortcut to vga_get
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*/
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static inline int vga_get_uninterruptible(struct pci_dev *pdev,
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unsigned int rsrc)
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{
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return vga_get(pdev, rsrc, 0);
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}
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/**
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* vga_tryget - try to acquire & lock legacy VGA resources
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*
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* @pdev: pci devivce of VGA card or NULL for system default
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* @rsrc: bit mask of resources to acquire and lock
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*
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* This function performs the same operation as vga_get(), but
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* will return an error (-EBUSY) instead of blocking if the resources
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* are already locked by another card. It can be called in any context
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*/
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#if defined(CONFIG_VGA_ARB)
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extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc);
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#else
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static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; }
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#endif
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/**
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* vga_put - release lock on legacy VGA resources
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*
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* @pdev: pci device of VGA card or NULL for system default
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* @rsrc: but mask of resource to release
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*
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* This function releases resources previously locked by vga_get()
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* or vga_tryget(). The resources aren't disabled right away, so
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* that a subsequence vga_get() on the same card will succeed
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* immediately. Resources have a counter, so locks are only
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* released if the counter reaches 0.
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*/
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#if defined(CONFIG_VGA_ARB)
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extern void vga_put(struct pci_dev *pdev, unsigned int rsrc);
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#else
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#define vga_put(pdev, rsrc)
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#endif
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/**
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* vga_default_device
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*
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* This can be defined by the platform. The default implementation
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* is rather dumb and will probably only work properly on single
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* vga card setups and/or x86 platforms.
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*
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* If your VGA default device is not PCI, you'll have to return
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* NULL here. In this case, I assume it will not conflict with
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* any PCI card. If this is not true, I'll have to define two archs
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* hooks for enabling/disabling the VGA default device if that is
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* possible. This may be a problem with real _ISA_ VGA cards, in
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* addition to a PCI one. I don't know at this point how to deal
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* with that card. Can theirs IOs be disabled at all ? If not, then
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* I suppose it's a matter of having the proper arch hook telling
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* us about it, so we basically never allow anybody to succeed a
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* vga_get()...
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*/
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#ifndef __ARCH_HAS_VGA_DEFAULT_DEVICE
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#ifdef CONFIG_VGA_ARB
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extern struct pci_dev *vga_default_device(void);
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extern void vga_set_default_device(struct pci_dev *pdev);
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#else
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static inline struct pci_dev *vga_default_device(void) { return NULL; };
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static inline void vga_set_default_device(struct pci_dev *pdev) { };
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#endif
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#endif
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/**
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* vga_conflicts
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*
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* Architectures should define this if they have several
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* independent PCI domains that can afford concurrent VGA
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* decoding
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*/
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#ifndef __ARCH_HAS_VGA_CONFLICT
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static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2)
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{
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return 1;
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}
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#endif
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/**
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* vga_client_register
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*
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* @pdev: pci device of the VGA client
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* @cookie: client cookie to be used in callbacks
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* @irq_set_state: irq state change callback
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* @set_vga_decode: vga decode change callback
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*
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* return value: 0 on success, -1 on failure
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* Register a client with the VGA arbitration logic
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*
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* Clients have two callback mechanisms they can use.
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* irq enable/disable callback -
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* If a client can't disable its GPUs VGA resources, then we
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* need to be able to ask it to turn off its irqs when we
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* turn off its mem and io decoding.
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* set_vga_decode
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* If a client can disable its GPU VGA resource, it will
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* get a callback from this to set the encode/decode state
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*
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* Rationale: we cannot disable VGA decode resources unconditionally
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* some single GPU laptops seem to require ACPI or BIOS access to the
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* VGA registers to control things like backlights etc.
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* Hopefully newer multi-GPU laptops do something saner, and desktops
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* won't have any special ACPI for this.
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* They driver will get a callback when VGA arbitration is first used
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* by userspace since we some older X servers have issues.
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*/
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#if defined(CONFIG_VGA_ARB)
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int vga_client_register(struct pci_dev *pdev, void *cookie,
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void (*irq_set_state)(void *cookie, bool state),
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unsigned int (*set_vga_decode)(void *cookie, bool state));
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#else
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static inline int vga_client_register(struct pci_dev *pdev, void *cookie,
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void (*irq_set_state)(void *cookie, bool state),
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unsigned int (*set_vga_decode)(void *cookie, bool state))
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{
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return 0;
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}
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#endif
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#endif /* LINUX_VGA_H */
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