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drm/irq: kerneldoc polish
- Integrate into the drm DocBook - Disable kerneldoc for functions not exported to drivers. - Properly document the new drm_vblank_on|off and add cautious comments explaining when drm_vblank_pre|post_modesets shouldn't be used. - General polish and OCD. v2: Polish as suggested by Thierry. Cc: Thierry Reding <thierry.reding@gmail.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Daniel Vetter
parent
8edffbb933
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@ -2519,6 +2519,10 @@ void (*disable_vblank) (struct drm_device *dev, int crtc);</synopsis>
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with a call to <function>drm_vblank_cleanup</function> in the driver
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<methodname>unload</methodname> operation handler.
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</para>
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<sect2>
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<title>Vertical Blanking and Interrupt Handling Functions Reference</title>
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!Edrivers/gpu/drm/drm_irq.c
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</sect2>
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</sect1>
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<!-- Internals: open/close, file operations and ioctls -->
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@ -2871,7 +2875,6 @@ int num_ioctls;</synopsis>
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</listitem>
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</varlistentry>
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</variablelist>
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<!--!Edrivers/char/drm/drm_irq.c-->
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</para>
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</sect1>
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@ -1,6 +1,5 @@
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/**
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* \file drm_irq.c
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* IRQ support
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/*
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* drm_irq.c IRQ and vblank support
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*
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* \author Rickard E. (Rik) Faith <faith@valinux.com>
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* \author Gareth Hughes <gareth@valinux.com>
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@ -156,6 +155,12 @@ static void vblank_disable_fn(unsigned long arg)
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spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
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}
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/**
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* drm_vblank_cleanup - cleanup vblank support
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* @dev: DRM device
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*
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* This function cleans up any resources allocated in drm_vblank_init.
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*/
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void drm_vblank_cleanup(struct drm_device *dev)
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{
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int crtc;
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@ -175,6 +180,16 @@ void drm_vblank_cleanup(struct drm_device *dev)
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}
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EXPORT_SYMBOL(drm_vblank_cleanup);
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/**
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* drm_vblank_init - initialize vblank support
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* @dev: drm_device
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* @num_crtcs: number of crtcs supported by @dev
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*
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* This function initializes vblank support for @num_crtcs display pipelines.
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*
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* Returns:
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* Zero on success or a negative error code on failure.
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*/
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int drm_vblank_init(struct drm_device *dev, int num_crtcs)
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{
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int i, ret = -ENOMEM;
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@ -238,13 +253,21 @@ static void drm_irq_vgaarb_nokms(void *cookie, bool state)
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}
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/**
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* Install IRQ handler.
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*
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* \param dev DRM device.
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* drm_irq_install - install IRQ handler
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* @dev: DRM device
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* @irq: IRQ number to install the handler for
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*
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* Initializes the IRQ related data. Installs the handler, calling the driver
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* \c irq_preinstall() and \c irq_postinstall() functions
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* before and after the installation.
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* irq_preinstall() and irq_postinstall() functions before and after the
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* installation.
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*
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* This is the simplified helper interface provided for drivers with no special
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* needs. Drivers which need to install interrupt handlers for multiple
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* interrupts must instead set drm_device->irq_enabled to signal the DRM core
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* that vblank interrupts are available.
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*
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* Returns:
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* Zero on success or a negative error code on failure.
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*/
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int drm_irq_install(struct drm_device *dev, int irq)
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{
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@ -304,11 +327,20 @@ int drm_irq_install(struct drm_device *dev, int irq)
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EXPORT_SYMBOL(drm_irq_install);
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/**
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* Uninstall the IRQ handler.
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* drm_irq_uninstall - uninstall the IRQ handler
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* @dev: DRM device
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*
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* \param dev DRM device.
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* Calls the driver's irq_uninstall() function and unregisters the IRQ handler.
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* This should only be called by drivers which used drm_irq_install() to set up
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* their interrupt handler. Other drivers must only reset
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* drm_device->irq_enabled to false.
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*
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* Calls the driver's \c irq_uninstall() function, and stops the irq.
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* Note that for kernel modesetting drivers it is a bug if this function fails.
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* The sanity checks are only to catch buggy user modesetting drivers which call
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* the same function through an ioctl.
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*
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* Returns:
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* Zero on success or a negative error code on failure.
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*/
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int drm_irq_uninstall(struct drm_device *dev)
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{
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@ -353,7 +385,7 @@ int drm_irq_uninstall(struct drm_device *dev)
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}
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EXPORT_SYMBOL(drm_irq_uninstall);
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/**
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/*
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* IRQ control ioctl.
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*
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* \param inode device inode.
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@ -406,15 +438,14 @@ int drm_control(struct drm_device *dev, void *data,
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}
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/**
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* drm_calc_timestamping_constants - Calculate vblank timestamp constants
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*
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* @crtc drm_crtc whose timestamp constants should be updated.
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* @mode display mode containing the scanout timings
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* drm_calc_timestamping_constants - calculate vblank timestamp constants
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* @crtc: drm_crtc whose timestamp constants should be updated.
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* @mode: display mode containing the scanout timings
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*
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* Calculate and store various constants which are later
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* needed by vblank and swap-completion timestamping, e.g,
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* by drm_calc_vbltimestamp_from_scanoutpos(). They are
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* derived from crtc's true scanout timing, so they take
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* derived from CRTC's true scanout timing, so they take
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* things like panel scaling or other adjustments into account.
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*/
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void drm_calc_timestamping_constants(struct drm_crtc *crtc,
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@ -459,11 +490,22 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc,
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EXPORT_SYMBOL(drm_calc_timestamping_constants);
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/**
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* drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
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* drivers. Implements calculation of exact vblank timestamps from
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* given drm_display_mode timings and current video scanout position
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* of a crtc. This can be called from within get_vblank_timestamp()
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* implementation of a kms driver to implement the actual timestamping.
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* drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper
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* @dev: DRM device
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* @crtc: Which CRTC's vblank timestamp to retrieve
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* @max_error: Desired maximum allowable error in timestamps (nanosecs)
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* On return contains true maximum error of timestamp
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* @vblank_time: Pointer to struct timeval which should receive the timestamp
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* @flags: Flags to pass to driver:
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* 0 = Default,
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* DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
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* @refcrtc: CRTC which defines scanout timing
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* @mode: mode which defines the scanout timings
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*
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* Implements calculation of exact vblank timestamps from given drm_display_mode
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* timings and current video scanout position of a CRTC. This can be called from
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* within get_vblank_timestamp() implementation of a kms driver to implement the
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* actual timestamping.
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*
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* Should return timestamps conforming to the OML_sync_control OpenML
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* extension specification. The timestamp corresponds to the end of
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@ -478,21 +520,11 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants);
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* returns as no operation if a doublescan or interlaced video mode is
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* active. Higher level code is expected to handle this.
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*
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* @dev: DRM device.
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* @crtc: Which crtc's vblank timestamp to retrieve.
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* @max_error: Desired maximum allowable error in timestamps (nanosecs).
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* On return contains true maximum error of timestamp.
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* @vblank_time: Pointer to struct timeval which should receive the timestamp.
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* @flags: Flags to pass to driver:
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* 0 = Default.
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* DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
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* @refcrtc: drm_crtc* of crtc which defines scanout timing.
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* @mode: mode which defines the scanout timings
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*
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* Returns negative value on error, failure or if not supported in current
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* Returns:
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* Negative value on error, failure or if not supported in current
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* video mode:
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*
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* -EINVAL - Invalid crtc.
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* -EINVAL - Invalid CRTC.
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* -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
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* -ENOTSUPP - Function not supported in current display mode.
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* -EIO - Failed, e.g., due to failed scanout position query.
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@ -641,23 +673,23 @@ static struct timeval get_drm_timestamp(void)
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/**
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* drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
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* vblank interval.
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*
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* vblank interval
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* @dev: DRM device
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* @crtc: which crtc's vblank timestamp to retrieve
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* @crtc: which CRTC's vblank timestamp to retrieve
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* @tvblank: Pointer to target struct timeval which should receive the timestamp
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* @flags: Flags to pass to driver:
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* 0 = Default.
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* DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
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* 0 = Default,
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* DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler
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*
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* Fetches the system timestamp corresponding to the time of the most recent
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* vblank interval on specified crtc. May call into kms-driver to
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* vblank interval on specified CRTC. May call into kms-driver to
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* compute the timestamp with a high-precision GPU specific method.
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*
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* Returns zero if timestamp originates from uncorrected do_gettimeofday()
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* call, i.e., it isn't very precisely locked to the true vblank.
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*
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* Returns non-zero if timestamp is considered to be very precise.
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* Returns:
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* Non-zero if timestamp is considered to be very precise, zero otherwise.
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*/
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u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
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struct timeval *tvblank, unsigned flags)
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@ -692,6 +724,9 @@ EXPORT_SYMBOL(drm_get_last_vbltimestamp);
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* Fetches the "cooked" vblank count value that represents the number of
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* vblank events since the system was booted, including lost events due to
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* modesetting activity.
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*
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* Returns:
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* The software vblank counter.
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*/
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u32 drm_vblank_count(struct drm_device *dev, int crtc)
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{
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@ -710,8 +745,7 @@ EXPORT_SYMBOL(drm_vblank_count);
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* Fetches the "cooked" vblank count value that represents the number of
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* vblank events since the system was booted, including lost events due to
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* modesetting activity. Returns corresponding system timestamp of the time
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* of the vblank interval that corresponds to the current value vblank counter
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* value.
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* of the vblank interval that corresponds to the current vblank counter value.
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*/
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u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
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struct timeval *vblanktime)
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@ -882,7 +916,7 @@ static int drm_vblank_enable(struct drm_device *dev, int crtc)
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* Acquire a reference count on vblank events to avoid having them disabled
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* while in use.
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*
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* RETURNS
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* Returns:
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* Zero on success, nonzero on failure.
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*/
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int drm_vblank_get(struct drm_device *dev, int crtc)
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@ -930,6 +964,13 @@ EXPORT_SYMBOL(drm_vblank_put);
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* drm_vblank_off - disable vblank events on a CRTC
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* @dev: DRM device
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* @crtc: CRTC in question
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*
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* Drivers can use this function to shut down the vblank interrupt handling when
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* disabling a crtc. This function ensures that the latest vblank frame count is
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* stored so that drm_vblank_on() can restore it again.
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*
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* Drivers must use this function when the hardware vblank counter can get
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* reset, e.g. when suspending.
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*/
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void drm_vblank_off(struct drm_device *dev, int crtc)
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{
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@ -966,6 +1007,11 @@ EXPORT_SYMBOL(drm_vblank_off);
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* drm_vblank_on - enable vblank events on a CRTC
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* @dev: DRM device
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* @crtc: CRTC in question
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*
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* This functions restores the vblank interrupt state captured with
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* drm_vblank_off() again. Note that calls to drm_vblank_on() and
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* drm_vblank_off() can be unbalanced and so can also be unconditionaly called
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* in driver load code to reflect the current hardware state of the crtc.
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*/
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void drm_vblank_on(struct drm_device *dev, int crtc)
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{
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@ -986,6 +1032,21 @@ EXPORT_SYMBOL(drm_vblank_on);
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*
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* Account for vblank events across mode setting events, which will likely
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* reset the hardware frame counter.
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*
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* This is done by grabbing a temporary vblank reference to ensure that the
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* vblank interrupt keeps running across the modeset sequence. With this the
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* software-side vblank frame counting will ensure that there are no jumps or
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* discontinuities.
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*
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* Unfortunately this approach is racy and also doesn't work when the vblank
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* interrupt stops running, e.g. across system suspend resume. It is therefore
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* highly recommended that drivers use the newer drm_vblank_off() and
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* drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when
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* using "cooked" software vblank frame counters and not relying on any hardware
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* counters.
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*
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* Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc
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* again.
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*/
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void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
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{
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@ -1007,6 +1068,14 @@ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
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}
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EXPORT_SYMBOL(drm_vblank_pre_modeset);
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/**
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* drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes
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* @dev: DRM device
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* @crtc: CRTC in question
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*
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* This function again drops the temporary vblank reference acquired in
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* drm_vblank_pre_modeset.
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*/
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void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
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{
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unsigned long irqflags;
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@ -1028,7 +1097,7 @@ void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
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}
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EXPORT_SYMBOL(drm_vblank_post_modeset);
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/**
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/*
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* drm_modeset_ctl - handle vblank event counter changes across mode switch
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* @DRM_IOCTL_ARGS: standard ioctl arguments
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*
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@ -1141,7 +1210,7 @@ err_put:
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return ret;
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}
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/**
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/*
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* Wait for VBLANK.
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*
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* \param inode device inode.
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@ -1152,7 +1221,7 @@ err_put:
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*
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* This function enables the vblank interrupt on the pipe requested, then
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* sleeps waiting for the requested sequence number to occur, and drops
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* the vblank interrupt refcount afterwards. (vblank irq disable follows that
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* the vblank interrupt refcount afterwards. (vblank IRQ disable follows that
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* after a timeout with no further vblank waits scheduled).
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*/
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int drm_wait_vblank(struct drm_device *dev, void *data,
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