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Commit f5752b38 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

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: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 8edffbb9

Documentation/DocBook/drm.tmpl

+4 −1
Original line number Diff line number Diff line
@@ -2519,6 +2519,10 @@ void (*disable_vblank) (struct drm_device *dev, int crtc);</synopsis> 
      with a call to <function>drm_vblank_cleanup</function> in the driver

      <methodname>unload</methodname> operation handler.

    </para>

    <sect2>

      <title>Vertical Blanking and Interrupt Handling Functions Reference</title>

!Edrivers/gpu/drm/drm_irq.c

    </sect2>

  </sect1>



  <!-- Internals: open/close, file operations and ioctls -->
@@ -2871,7 +2875,6 @@ int num_ioctls;</synopsis> 
            </listitem>

          </varlistentry>

        </variablelist>

<!--!Edrivers/char/drm/drm_irq.c-->

      </para>

    </sect1>

drivers/gpu/drm/drm_irq.c

+117 −48
Original line number Diff line number Diff line 
/**

 * \file drm_irq.c

 * IRQ support

/*

 * drm_irq.c IRQ and vblank support

 *

 * \author Rickard E. (Rik) Faith <faith@valinux.com>

 * \author Gareth Hughes <gareth@valinux.com>
@@ -156,6 +155,12 @@ static void vblank_disable_fn(unsigned long arg) 
	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

}



/**

 * drm_vblank_cleanup - cleanup vblank support

 * @dev: DRM device

 *

 * This function cleans up any resources allocated in drm_vblank_init.

 */

void drm_vblank_cleanup(struct drm_device *dev)

{

	int crtc;
@@ -175,6 +180,16 @@ void drm_vblank_cleanup(struct drm_device *dev) 
}

EXPORT_SYMBOL(drm_vblank_cleanup);



/**

 * drm_vblank_init - initialize vblank support

 * @dev: drm_device

 * @num_crtcs: number of crtcs supported by @dev

 *

 * This function initializes vblank support for @num_crtcs display pipelines.

 *

 * Returns:

 * Zero on success or a negative error code on failure.

 */

int drm_vblank_init(struct drm_device *dev, int num_crtcs)

{

	int i, ret = -ENOMEM;
@@ -238,13 +253,21 @@ static void drm_irq_vgaarb_nokms(void *cookie, bool state) 
}



/**

 * Install IRQ handler.

 *

 * \param dev DRM device.

 * drm_irq_install - install IRQ handler

 * @dev: DRM device

 * @irq: IRQ number to install the handler for

 *

 * Initializes the IRQ related data. Installs the handler, calling the driver

 * \c irq_preinstall() and \c irq_postinstall() functions

 * before and after the installation.

 * irq_preinstall() and irq_postinstall() functions before and after the

 * installation.

 *

 * This is the simplified helper interface provided for drivers with no special

 * needs. Drivers which need to install interrupt handlers for multiple

 * interrupts must instead set drm_device->irq_enabled to signal the DRM core

 * that vblank interrupts are available.

 *

 * Returns:

 * Zero on success or a negative error code on failure.

 */

int drm_irq_install(struct drm_device *dev, int irq)

{
@@ -304,11 +327,20 @@ int drm_irq_install(struct drm_device *dev, int irq) 
EXPORT_SYMBOL(drm_irq_install);



/**

 * Uninstall the IRQ handler.

 * drm_irq_uninstall - uninstall the IRQ handler

 * @dev: DRM device

 *

 * Calls the driver's irq_uninstall() function and unregisters the IRQ handler.

 * This should only be called by drivers which used drm_irq_install() to set up

 * their interrupt handler. Other drivers must only reset

 * drm_device->irq_enabled to false.

 *

 * \param dev DRM device.

 * Note that for kernel modesetting drivers it is a bug if this function fails.

 * The sanity checks are only to catch buggy user modesetting drivers which call

 * the same function through an ioctl.

 *

 * Calls the driver's \c irq_uninstall() function, and stops the irq.

 * Returns:

 * Zero on success or a negative error code on failure.

 */

int drm_irq_uninstall(struct drm_device *dev)

{
@@ -353,7 +385,7 @@ int drm_irq_uninstall(struct drm_device *dev) 
}

EXPORT_SYMBOL(drm_irq_uninstall);



/**

/*

 * IRQ control ioctl.

 *

 * \param inode device inode.
@@ -406,15 +438,14 @@ int drm_control(struct drm_device *dev, void *data, 
}



/**

 * drm_calc_timestamping_constants - Calculate vblank timestamp constants

 *

 * @crtc drm_crtc whose timestamp constants should be updated.

 * @mode display mode containing the scanout timings

 * drm_calc_timestamping_constants - calculate vblank timestamp constants

 * @crtc: drm_crtc whose timestamp constants should be updated.

 * @mode: display mode containing the scanout timings

 *

 * Calculate and store various constants which are later

 * needed by vblank and swap-completion timestamping, e.g,

 * by drm_calc_vbltimestamp_from_scanoutpos(). They are

 * derived from crtc's true scanout timing, so they take

 * derived from CRTC's true scanout timing, so they take

 * things like panel scaling or other adjustments into account.

 */

void drm_calc_timestamping_constants(struct drm_crtc *crtc,
@@ -459,11 +490,22 @@ void drm_calc_timestamping_constants(struct drm_crtc *crtc, 
EXPORT_SYMBOL(drm_calc_timestamping_constants);



/**

 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms

 * drivers. Implements calculation of exact vblank timestamps from

 * given drm_display_mode timings and current video scanout position

 * of a crtc. This can be called from within get_vblank_timestamp()

 * implementation of a kms driver to implement the actual timestamping.

 * drm_calc_vbltimestamp_from_scanoutpos - precise vblank timestamp helper

 * @dev: DRM device

 * @crtc: Which CRTC's vblank timestamp to retrieve

 * @max_error: Desired maximum allowable error in timestamps (nanosecs)

 *             On return contains true maximum error of timestamp

 * @vblank_time: Pointer to struct timeval which should receive the timestamp

 * @flags: Flags to pass to driver:

 *         0 = Default,

 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler

 * @refcrtc: CRTC which defines scanout timing

 * @mode: mode which defines the scanout timings

 *

 * Implements calculation of exact vblank timestamps from given drm_display_mode

 * timings and current video scanout position of a CRTC. This can be called from

 * within get_vblank_timestamp() implementation of a kms driver to implement the

 * actual timestamping.

 *

 * Should return timestamps conforming to the OML_sync_control OpenML

 * extension specification. The timestamp corresponds to the end of
@@ -478,21 +520,11 @@ EXPORT_SYMBOL(drm_calc_timestamping_constants); 
 * returns as no operation if a doublescan or interlaced video mode is

 * active. Higher level code is expected to handle this.

 *

 * @dev: DRM device.

 * @crtc: Which crtc's vblank timestamp to retrieve.

 * @max_error: Desired maximum allowable error in timestamps (nanosecs).

 *             On return contains true maximum error of timestamp.

 * @vblank_time: Pointer to struct timeval which should receive the timestamp.

 * @flags: Flags to pass to driver:

 *         0 = Default.

 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.

 * @refcrtc: drm_crtc* of crtc which defines scanout timing.

 * @mode: mode which defines the scanout timings

 *

 * Returns negative value on error, failure or if not supported in current

 * Returns:

 * Negative value on error, failure or if not supported in current

 * video mode:

 *

 * -EINVAL   - Invalid crtc.

 * -EINVAL   - Invalid CRTC.

 * -EAGAIN   - Temporary unavailable, e.g., called before initial modeset.

 * -ENOTSUPP - Function not supported in current display mode.

 * -EIO      - Failed, e.g., due to failed scanout position query.
@@ -641,23 +673,23 @@ static struct timeval get_drm_timestamp(void) 


/**

 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent

 * vblank interval.

 *

 * 			       vblank interval

 * @dev: DRM device

 * @crtc: which crtc's vblank timestamp to retrieve

 * @crtc: which CRTC's vblank timestamp to retrieve

 * @tvblank: Pointer to target struct timeval which should receive the timestamp

 * @flags: Flags to pass to driver:

 *         0 = Default.

 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.

 *         0 = Default,

 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl IRQ handler

 *

 * Fetches the system timestamp corresponding to the time of the most recent

 * vblank interval on specified crtc. May call into kms-driver to

 * vblank interval on specified CRTC. May call into kms-driver to

 * compute the timestamp with a high-precision GPU specific method.

 *

 * Returns zero if timestamp originates from uncorrected do_gettimeofday()

 * call, i.e., it isn't very precisely locked to the true vblank.

 *

 * Returns non-zero if timestamp is considered to be very precise.

 * Returns:

 * Non-zero if timestamp is considered to be very precise, zero otherwise.

 */

u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,

			      struct timeval *tvblank, unsigned flags)
@@ -692,6 +724,9 @@ EXPORT_SYMBOL(drm_get_last_vbltimestamp); 
 * Fetches the "cooked" vblank count value that represents the number of

 * vblank events since the system was booted, including lost events due to

 * modesetting activity.

 *

 * Returns:

 * The software vblank counter.

 */

u32 drm_vblank_count(struct drm_device *dev, int crtc)

{
@@ -710,8 +745,7 @@ EXPORT_SYMBOL(drm_vblank_count); 
 * Fetches the "cooked" vblank count value that represents the number of

 * vblank events since the system was booted, including lost events due to

 * modesetting activity. Returns corresponding system timestamp of the time

 * of the vblank interval that corresponds to the current value vblank counter

 * value.

 * of the vblank interval that corresponds to the current vblank counter value.

 */

u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,

			      struct timeval *vblanktime)
@@ -882,7 +916,7 @@ static int drm_vblank_enable(struct drm_device *dev, int crtc) 
 * Acquire a reference count on vblank events to avoid having them disabled

 * while in use.

 *

 * RETURNS

 * Returns:

 * Zero on success, nonzero on failure.

 */

int drm_vblank_get(struct drm_device *dev, int crtc)
@@ -930,6 +964,13 @@ EXPORT_SYMBOL(drm_vblank_put); 
 * drm_vblank_off - disable vblank events on a CRTC

 * @dev: DRM device

 * @crtc: CRTC in question

 *

 * Drivers can use this function to shut down the vblank interrupt handling when

 * disabling a crtc. This function ensures that the latest vblank frame count is

 * stored so that drm_vblank_on() can restore it again.

 *

 * Drivers must use this function when the hardware vblank counter can get

 * reset, e.g. when suspending.

 */

void drm_vblank_off(struct drm_device *dev, int crtc)

{
@@ -966,6 +1007,11 @@ EXPORT_SYMBOL(drm_vblank_off); 
 * drm_vblank_on - enable vblank events on a CRTC

 * @dev: DRM device

 * @crtc: CRTC in question

 *

 * This functions restores the vblank interrupt state captured with

 * drm_vblank_off() again. Note that calls to drm_vblank_on() and

 * drm_vblank_off() can be unbalanced and so can also be unconditionaly called

 * in driver load code to reflect the current hardware state of the crtc.

 */

void drm_vblank_on(struct drm_device *dev, int crtc)

{
@@ -986,6 +1032,21 @@ EXPORT_SYMBOL(drm_vblank_on); 
 *

 * Account for vblank events across mode setting events, which will likely

 * reset the hardware frame counter.

 *

 * This is done by grabbing a temporary vblank reference to ensure that the

 * vblank interrupt keeps running across the modeset sequence. With this the

 * software-side vblank frame counting will ensure that there are no jumps or

 * discontinuities.

 *

 * Unfortunately this approach is racy and also doesn't work when the vblank

 * interrupt stops running, e.g. across system suspend resume. It is therefore

 * highly recommended that drivers use the newer drm_vblank_off() and

 * drm_vblank_on() instead. drm_vblank_pre_modeset() only works correctly when

 * using "cooked" software vblank frame counters and not relying on any hardware

 * counters.

 *

 * Drivers must call drm_vblank_post_modeset() when re-enabling the same crtc

 * again.

 */

void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)

{
@@ -1007,6 +1068,14 @@ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) 
}

EXPORT_SYMBOL(drm_vblank_pre_modeset);



/**

 * drm_vblank_post_modeset - undo drm_vblank_pre_modeset changes

 * @dev: DRM device

 * @crtc: CRTC in question

 *

 * This function again drops the temporary vblank reference acquired in

 * drm_vblank_pre_modeset.

 */

void drm_vblank_post_modeset(struct drm_device *dev, int crtc)

{

	unsigned long irqflags;
@@ -1028,7 +1097,7 @@ void drm_vblank_post_modeset(struct drm_device *dev, int crtc) 
}

EXPORT_SYMBOL(drm_vblank_post_modeset);



/**

/*

 * drm_modeset_ctl - handle vblank event counter changes across mode switch

 * @DRM_IOCTL_ARGS: standard ioctl arguments

 *
@@ -1141,7 +1210,7 @@ err_put: 
	return ret;

}



/**

/*

 * Wait for VBLANK.

 *

 * \param inode device inode.
@@ -1152,7 +1221,7 @@ err_put: 
 *

 * This function enables the vblank interrupt on the pipe requested, then

 * sleeps waiting for the requested sequence number to occur, and drops

 * the vblank interrupt refcount afterwards. (vblank irq disable follows that

 * the vblank interrupt refcount afterwards. (vblank IRQ disable follows that

 * after a timeout with no further vblank waits scheduled).

 */

int drm_wait_vblank(struct drm_device *dev, void *data,