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vgaarbiter: rst-ifiy and polish kerneldoc

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Move the documentation into Documentation/gpu, link it up and pull in
the kernel doc.

No actual text changes except that I did polish the kerneldoc a bit,
especially for vga_client_register().

v2: Remove some rst from vga-switcheroo.rst that I don't understand,
but which seems to be the reason why the new vgaarbiter.rst sometimes
drops out of the sidebar index.

v3: Drop one level of headings and clarify the vgaarb one a bit.

v4: Fix some typos (Sean).

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471034937-651-20-git-send-email-daniel.vetter@ffwll.ch
This commit is contained in:
Daniel Vetter
2016-08-12 22:48:56 +02:00
parent b3c6c8bfe3
commit b754b35b08
5 changed files with 196 additions and 188 deletions
Download Patch File Download Diff File Expand all files Collapse all files

128
include/linux/vgaarb.h
View File

@@ -73,34 +73,6 @@ static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
unsigned int decodes) { };
#endif
/**
* vga_get - acquire & locks VGA resources
*
* @pdev: pci device of the VGA card or NULL for the system default
* @rsrc: bit mask of resources to acquire and lock
* @interruptible: blocking should be interruptible by signals ?
*
* This function acquires VGA resources for the given
* card and mark those resources locked. If the resource requested
* are "normal" (and not legacy) resources, the arbiter will first check
* whether the card is doing legacy decoding for that type of resource. If
* yes, the lock is "converted" into a legacy resource lock.
* The arbiter will first look for all VGA cards that might conflict
* and disable their IOs and/or Memory access, including VGA forwarding
* on P2P bridges if necessary, so that the requested resources can
* be used. Then, the card is marked as locking these resources and
* the IO and/or Memory accesse are enabled on the card (including
* VGA forwarding on parent P2P bridges if any).
* This function will block if some conflicting card is already locking
* one of the required resources (or any resource on a different bus
* segment, since P2P bridges don't differenciate VGA memory and IO
* afaik). You can indicate whether this blocking should be interruptible
* by a signal (for userland interface) or not.
* Must not be called at interrupt time or in atomic context.
* If the card already owns the resources, the function succeeds.
* Nested calls are supported (a per-resource counter is maintained)
*/
#if defined(CONFIG_VGA_ARB)
extern int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interruptible);
#else
@@ -108,11 +80,14 @@ static inline int vga_get(struct pci_dev *pdev, unsigned int rsrc, int interrupt
#endif
/**
* vga_get_interruptible
* vga_get_interruptible
* @pdev: pci device of the VGA card or NULL for the system default
* @rsrc: bit mask of resources to acquire and lock
*
* Shortcut to vga_get
* Shortcut to vga_get with interruptible set to true.
*
* On success, release the VGA resource again with vga_put().
*/
static inline int vga_get_interruptible(struct pci_dev *pdev,
unsigned int rsrc)
{
@@ -120,47 +95,26 @@ static inline int vga_get_interruptible(struct pci_dev *pdev,
}
/**
* vga_get_uninterruptible
* vga_get_uninterruptible - shortcut to vga_get()
* @pdev: pci device of the VGA card or NULL for the system default
* @rsrc: bit mask of resources to acquire and lock
*
* Shortcut to vga_get
* Shortcut to vga_get with interruptible set to false.
*
* On success, release the VGA resource again with vga_put().
*/
static inline int vga_get_uninterruptible(struct pci_dev *pdev,
unsigned int rsrc)
{
return vga_get(pdev, rsrc, 0);
}
/**
* vga_tryget - try to acquire & lock legacy VGA resources
*
* @pdev: pci devivce of VGA card or NULL for system default
* @rsrc: bit mask of resources to acquire and lock
*
* This function performs the same operation as vga_get(), but
* will return an error (-EBUSY) instead of blocking if the resources
* are already locked by another card. It can be called in any context
*/
#if defined(CONFIG_VGA_ARB)
extern int vga_tryget(struct pci_dev *pdev, unsigned int rsrc);
#else
static inline int vga_tryget(struct pci_dev *pdev, unsigned int rsrc) { return 0; }
#endif
/**
* vga_put - release lock on legacy VGA resources
*
* @pdev: pci device of VGA card or NULL for system default
* @rsrc: but mask of resource to release
*
* This function releases resources previously locked by vga_get()
* or vga_tryget(). The resources aren't disabled right away, so
* that a subsequence vga_get() on the same card will succeed
* immediately. Resources have a counter, so locks are only
* released if the counter reaches 0.
*/
#if defined(CONFIG_VGA_ARB)
extern void vga_put(struct pci_dev *pdev, unsigned int rsrc);
#else
@@ -168,25 +122,6 @@ extern void vga_put(struct pci_dev *pdev, unsigned int rsrc);
#endif
/**
* vga_default_device
*
* This can be defined by the platform. The default implementation
* is rather dumb and will probably only work properly on single
* vga card setups and/or x86 platforms.
*
* If your VGA default device is not PCI, you'll have to return
* NULL here. In this case, I assume it will not conflict with
* any PCI card. If this is not true, I'll have to define two archs
* hooks for enabling/disabling the VGA default device if that is
* possible. This may be a problem with real _ISA_ VGA cards, in
* addition to a PCI one. I don't know at this point how to deal
* with that card. Can theirs IOs be disabled at all ? If not, then
* I suppose it's a matter of having the proper arch hook telling
* us about it, so we basically never allow anybody to succeed a
* vga_get()...
*/
#ifdef CONFIG_VGA_ARB
extern struct pci_dev *vga_default_device(void);
extern void vga_set_default_device(struct pci_dev *pdev);
@@ -195,14 +130,11 @@ static inline struct pci_dev *vga_default_device(void) { return NULL; };
static inline void vga_set_default_device(struct pci_dev *pdev) { };
#endif
/**
* vga_conflicts
*
* Architectures should define this if they have several
* independent PCI domains that can afford concurrent VGA
* decoding
/*
* Architectures should define this if they have several
* independent PCI domains that can afford concurrent VGA
* decoding
*/
#ifndef __ARCH_HAS_VGA_CONFLICT
static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2)
{
@@ -210,34 +142,6 @@ static inline int vga_conflicts(struct pci_dev *p1, struct pci_dev *p2)
}
#endif
/**
* vga_client_register
*
* @pdev: pci device of the VGA client
* @cookie: client cookie to be used in callbacks
* @irq_set_state: irq state change callback
* @set_vga_decode: vga decode change callback
*
* return value: 0 on success, -1 on failure
* Register a client with the VGA arbitration logic
*
* Clients have two callback mechanisms they can use.
* irq enable/disable callback -
* If a client can't disable its GPUs VGA resources, then we
* need to be able to ask it to turn off its irqs when we
* turn off its mem and io decoding.
* set_vga_decode
* If a client can disable its GPU VGA resource, it will
* get a callback from this to set the encode/decode state
*
* Rationale: we cannot disable VGA decode resources unconditionally
* some single GPU laptops seem to require ACPI or BIOS access to the
* VGA registers to control things like backlights etc.
* Hopefully newer multi-GPU laptops do something saner, and desktops
* won't have any special ACPI for this.
* They driver will get a callback when VGA arbitration is first used
* by userspace since we some older X servers have issues.
*/
#if defined(CONFIG_VGA_ARB)
int vga_client_register(struct pci_dev *pdev, void *cookie,
void (*irq_set_state)(void *cookie, bool state),