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authorDaniel Vetter <daniel.vetter@ffwll.ch>2016-08-12 22:48:56 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-08-16 18:49:56 +0200
commitb754b35b089ddfea3ff7b9b1d2e99e61d726d177 (patch)
tree9875b958a0e61f8e3ec2dd2f31aeb50e60c90bd5 /include/linux/vgaarb.h
parentb3c6c8bfe378309f8185d591579a3cb3aa2fe2e8 (diff)
vgaarbiter: rst-ifiy and polish kerneldoc
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
Diffstat (limited to 'include/linux/vgaarb.h')
-rw-r--r--include/linux/vgaarb.h128
1 files changed, 16 insertions, 112 deletions
diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
index 8c3b412d84df..ee162e3e879b 100644
--- a/include/linux/vgaarb.h
+++ b/include/linux/vgaarb.h
@@ -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),