Merge branch 'for_2.6.35rc' of git://git.pwsan.com/linux-2.6 into omap-fixes-for...

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / gpu / drm / drm_irq.c

/**
 * \file drm_irq.c
 * IRQ support
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
 *
 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include "drmP.h"

#include <linux/interrupt.h>    /* For task queue support */
#include <linux/slab.h>

#include <linux/vgaarb.h>
/**
 * Get interrupt from bus id.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_irq_busid structure.
 * \return zero on success or a negative number on failure.
 *
 * Finds the PCI device with the specified bus id and gets its IRQ number.
 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
 * to that of the device that this DRM instance attached to.
 */
int drm_irq_by_busid(struct drm_device *dev, void *data,
                     struct drm_file *file_priv)
{
        struct drm_irq_busid *p = data;

        if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                return -EINVAL;

        if ((p->busnum >> 8) != drm_get_pci_domain(dev) ||
            (p->busnum & 0xff) != dev->pdev->bus->number ||
            p->devnum != PCI_SLOT(dev->pdev->devfn) || p->funcnum != PCI_FUNC(dev->pdev->devfn))
                return -EINVAL;

        p->irq = dev->pdev->irq;

        DRM_DEBUG("%d:%d:%d => IRQ %d\n", p->busnum, p->devnum, p->funcnum,
                  p->irq);

        return 0;
}

static void vblank_disable_fn(unsigned long arg)
{
        struct drm_device *dev = (struct drm_device *)arg;
        unsigned long irqflags;
        int i;

        if (!dev->vblank_disable_allowed)
                return;

        for (i = 0; i < dev->num_crtcs; i++) {
                spin_lock_irqsave(&dev->vbl_lock, irqflags);
                if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
                    dev->vblank_enabled[i]) {
                        DRM_DEBUG("disabling vblank on crtc %d\n", i);
                        dev->last_vblank[i] =
                                dev->driver->get_vblank_counter(dev, i);
                        dev->driver->disable_vblank(dev, i);
                        dev->vblank_enabled[i] = 0;
                }
                spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
        }
}

void drm_vblank_cleanup(struct drm_device *dev)
{
        /* Bail if the driver didn't call drm_vblank_init() */
        if (dev->num_crtcs == 0)
                return;

        del_timer(&dev->vblank_disable_timer);

        vblank_disable_fn((unsigned long)dev);

        kfree(dev->vbl_queue);
        kfree(dev->_vblank_count);
        kfree(dev->vblank_refcount);
        kfree(dev->vblank_enabled);
        kfree(dev->last_vblank);
        kfree(dev->last_vblank_wait);
        kfree(dev->vblank_inmodeset);

        dev->num_crtcs = 0;
}
EXPORT_SYMBOL(drm_vblank_cleanup);

int drm_vblank_init(struct drm_device *dev, int num_crtcs)
{
        int i, ret = -ENOMEM;

        setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
                    (unsigned long)dev);
        spin_lock_init(&dev->vbl_lock);
        dev->num_crtcs = num_crtcs;

        dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs,
                                 GFP_KERNEL);
        if (!dev->vbl_queue)
                goto err;

        dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL);
        if (!dev->_vblank_count)
                goto err;

        dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs,
                                       GFP_KERNEL);
        if (!dev->vblank_refcount)
                goto err;

        dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
        if (!dev->vblank_enabled)
                goto err;

        dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
        if (!dev->last_vblank)
                goto err;

        dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
        if (!dev->last_vblank_wait)
                goto err;

        dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
        if (!dev->vblank_inmodeset)
                goto err;

        /* Zero per-crtc vblank stuff */
        for (i = 0; i < num_crtcs; i++) {
                init_waitqueue_head(&dev->vbl_queue[i]);
                atomic_set(&dev->_vblank_count[i], 0);
                atomic_set(&dev->vblank_refcount[i], 0);
        }

        dev->vblank_disable_allowed = 0;
        return 0;

err:
        drm_vblank_cleanup(dev);
        return ret;
}
EXPORT_SYMBOL(drm_vblank_init);

static void drm_irq_vgaarb_nokms(void *cookie, bool state)
{
        struct drm_device *dev = cookie;

        if (dev->driver->vgaarb_irq) {
                dev->driver->vgaarb_irq(dev, state);
                return;
        }

        if (!dev->irq_enabled)
                return;

        if (state)
                dev->driver->irq_uninstall(dev);
        else {
                dev->driver->irq_preinstall(dev);
                dev->driver->irq_postinstall(dev);
        }
}

/**
 * Install IRQ handler.
 *
 * \param dev DRM device.
 *
 * Initializes the IRQ related data. Installs the handler, calling the driver
 * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
 * before and after the installation.
 */
int drm_irq_install(struct drm_device *dev)
{
        int ret = 0;
        unsigned long sh_flags = 0;
        char *irqname;

        if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                return -EINVAL;

        if (dev->pdev->irq == 0)
                return -EINVAL;

        mutex_lock(&dev->struct_mutex);

        /* Driver must have been initialized */
        if (!dev->dev_private) {
                mutex_unlock(&dev->struct_mutex);
                return -EINVAL;
        }

        if (dev->irq_enabled) {
                mutex_unlock(&dev->struct_mutex);
                return -EBUSY;
        }
        dev->irq_enabled = 1;
        mutex_unlock(&dev->struct_mutex);

        DRM_DEBUG("irq=%d\n", dev->pdev->irq);

        /* Before installing handler */
        dev->driver->irq_preinstall(dev);

        /* Install handler */
        if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
                sh_flags = IRQF_SHARED;

        if (dev->devname)
                irqname = dev->devname;
        else
                irqname = dev->driver->name;

        ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
                          sh_flags, irqname, dev);

        if (ret < 0) {
                mutex_lock(&dev->struct_mutex);
                dev->irq_enabled = 0;
                mutex_unlock(&dev->struct_mutex);
                return ret;
        }

        if (!drm_core_check_feature(dev, DRIVER_MODESET))
                vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);

        /* After installing handler */
        ret = dev->driver->irq_postinstall(dev);
        if (ret < 0) {
                mutex_lock(&dev->struct_mutex);
                dev->irq_enabled = 0;
                mutex_unlock(&dev->struct_mutex);
        }

        return ret;
}
EXPORT_SYMBOL(drm_irq_install);

/**
 * Uninstall the IRQ handler.
 *
 * \param dev DRM device.
 *
 * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
 */
int drm_irq_uninstall(struct drm_device * dev)
{
        unsigned long irqflags;
        int irq_enabled, i;

        if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                return -EINVAL;

        mutex_lock(&dev->struct_mutex);
        irq_enabled = dev->irq_enabled;
        dev->irq_enabled = 0;
        mutex_unlock(&dev->struct_mutex);

        /*
         * Wake up any waiters so they don't hang.
         */
        spin_lock_irqsave(&dev->vbl_lock, irqflags);
        for (i = 0; i < dev->num_crtcs; i++) {
                DRM_WAKEUP(&dev->vbl_queue[i]);
                dev->vblank_enabled[i] = 0;
                dev->last_vblank[i] = dev->driver->get_vblank_counter(dev, i);
        }
        spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

        if (!irq_enabled)
                return -EINVAL;

        DRM_DEBUG("irq=%d\n", dev->pdev->irq);

        if (!drm_core_check_feature(dev, DRIVER_MODESET))
                vga_client_register(dev->pdev, NULL, NULL, NULL);

        dev->driver->irq_uninstall(dev);

        free_irq(dev->pdev->irq, dev);

        return 0;
}
EXPORT_SYMBOL(drm_irq_uninstall);

/**
 * IRQ control ioctl.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_control structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls irq_install() or irq_uninstall() according to \p arg.
 */
int drm_control(struct drm_device *dev, void *data,
                struct drm_file *file_priv)
{
        struct drm_control *ctl = data;

        /* if we haven't irq we fallback for compatibility reasons - this used to be a separate function in drm_dma.h */


        switch (ctl->func) {
        case DRM_INST_HANDLER:
                if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                        return 0;
                if (drm_core_check_feature(dev, DRIVER_MODESET))
                        return 0;
                if (dev->if_version < DRM_IF_VERSION(1, 2) &&
                    ctl->irq != dev->pdev->irq)
                        return -EINVAL;
                return drm_irq_install(dev);
        case DRM_UNINST_HANDLER:
                if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                        return 0;
                if (drm_core_check_feature(dev, DRIVER_MODESET))
                        return 0;
                return drm_irq_uninstall(dev);
        default:
                return -EINVAL;
        }
}

/**
 * drm_vblank_count - retrieve "cooked" vblank counter value
 * @dev: DRM device
 * @crtc: which counter to retrieve
 *
 * 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.
 */
u32 drm_vblank_count(struct drm_device *dev, int crtc)
{
        return atomic_read(&dev->_vblank_count[crtc]);
}
EXPORT_SYMBOL(drm_vblank_count);

/**
 * drm_update_vblank_count - update the master vblank counter
 * @dev: DRM device
 * @crtc: counter to update
 *
 * Call back into the driver to update the appropriate vblank counter
 * (specified by @crtc).  Deal with wraparound, if it occurred, and
 * update the last read value so we can deal with wraparound on the next
 * call if necessary.
 *
 * Only necessary when going from off->on, to account for frames we
 * didn't get an interrupt for.
 *
 * Note: caller must hold dev->vbl_lock since this reads & writes
 * device vblank fields.
 */
static void drm_update_vblank_count(struct drm_device *dev, int crtc)
{
        u32 cur_vblank, diff;

        /*
         * Interrupts were disabled prior to this call, so deal with counter
         * wrap if needed.
         * NOTE!  It's possible we lost a full dev->max_vblank_count events
         * here if the register is small or we had vblank interrupts off for
         * a long time.
         */
        cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
        diff = cur_vblank - dev->last_vblank[crtc];
        if (cur_vblank < dev->last_vblank[crtc]) {
                diff += dev->max_vblank_count;

                DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
                          crtc, dev->last_vblank[crtc], cur_vblank, diff);
        }

        DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
                  crtc, diff);

        atomic_add(diff, &dev->_vblank_count[crtc]);
}

/**
 * drm_vblank_get - get a reference count on vblank events
 * @dev: DRM device
 * @crtc: which CRTC to own
 *
 * Acquire a reference count on vblank events to avoid having them disabled
 * while in use.
 *
 * RETURNS
 * Zero on success, nonzero on failure.
 */
int drm_vblank_get(struct drm_device *dev, int crtc)
{
        unsigned long irqflags;
        int ret = 0;

        spin_lock_irqsave(&dev->vbl_lock, irqflags);
        /* Going from 0->1 means we have to enable interrupts again */
        if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) {
                if (!dev->vblank_enabled[crtc]) {
                        ret = dev->driver->enable_vblank(dev, crtc);
                        DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
                        if (ret)
                                atomic_dec(&dev->vblank_refcount[crtc]);
                        else {
                                dev->vblank_enabled[crtc] = 1;
                                drm_update_vblank_count(dev, crtc);
                        }
                }
        } else {
                if (!dev->vblank_enabled[crtc]) {
                        atomic_dec(&dev->vblank_refcount[crtc]);
                        ret = -EINVAL;
                }
        }
        spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

        return ret;
}
EXPORT_SYMBOL(drm_vblank_get);

/**
 * drm_vblank_put - give up ownership of vblank events
 * @dev: DRM device
 * @crtc: which counter to give up
 *
 * Release ownership of a given vblank counter, turning off interrupts
 * if possible.
 */
void drm_vblank_put(struct drm_device *dev, int crtc)
{
        BUG_ON (atomic_read (&dev->vblank_refcount[crtc]) == 0);

        /* Last user schedules interrupt disable */
        if (atomic_dec_and_test(&dev->vblank_refcount[crtc]))
                mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ);
}
EXPORT_SYMBOL(drm_vblank_put);

void drm_vblank_off(struct drm_device *dev, int crtc)
{
        unsigned long irqflags;

        spin_lock_irqsave(&dev->vbl_lock, irqflags);
        dev->driver->disable_vblank(dev, crtc);
        DRM_WAKEUP(&dev->vbl_queue[crtc]);
        dev->vblank_enabled[crtc] = 0;
        dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc);
        spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
EXPORT_SYMBOL(drm_vblank_off);

/**
 * drm_vblank_pre_modeset - account for vblanks across mode sets
 * @dev: DRM device
 * @crtc: CRTC in question
 * @post: post or pre mode set?
 *
 * Account for vblank events across mode setting events, which will likely
 * reset the hardware frame counter.
 */
void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
{
        /* vblank is not initialized (IRQ not installed ?) */
        if (!dev->num_crtcs)
                return;
        /*
         * To avoid all the problems that might happen if interrupts
         * were enabled/disabled around or between these calls, we just
         * have the kernel take a reference on the CRTC (just once though
         * to avoid corrupting the count if multiple, mismatch calls occur),
         * so that interrupts remain enabled in the interim.
         */
        if (!dev->vblank_inmodeset[crtc]) {
                dev->vblank_inmodeset[crtc] = 0x1;
                if (drm_vblank_get(dev, crtc) == 0)
                        dev->vblank_inmodeset[crtc] |= 0x2;
        }
}
EXPORT_SYMBOL(drm_vblank_pre_modeset);

void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
{
        unsigned long irqflags;

        if (dev->vblank_inmodeset[crtc]) {
                spin_lock_irqsave(&dev->vbl_lock, irqflags);
                dev->vblank_disable_allowed = 1;
                spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

                if (dev->vblank_inmodeset[crtc] & 0x2)
                        drm_vblank_put(dev, crtc);

                dev->vblank_inmodeset[crtc] = 0;
        }
}
EXPORT_SYMBOL(drm_vblank_post_modeset);

/**
 * drm_modeset_ctl - handle vblank event counter changes across mode switch
 * @DRM_IOCTL_ARGS: standard ioctl arguments
 *
 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
 * ioctls around modesetting so that any lost vblank events are accounted for.
 *
 * Generally the counter will reset across mode sets.  If interrupts are
 * enabled around this call, we don't have to do anything since the counter
 * will have already been incremented.
 */
int drm_modeset_ctl(struct drm_device *dev, void *data,
                    struct drm_file *file_priv)
{
        struct drm_modeset_ctl *modeset = data;
        int crtc, ret = 0;

        /* If drm_vblank_init() hasn't been called yet, just no-op */
        if (!dev->num_crtcs)
                goto out;

        crtc = modeset->crtc;
        if (crtc >= dev->num_crtcs) {
                ret = -EINVAL;
                goto out;
        }

        switch (modeset->cmd) {
        case _DRM_PRE_MODESET:
                drm_vblank_pre_modeset(dev, crtc);
                break;
        case _DRM_POST_MODESET:
                drm_vblank_post_modeset(dev, crtc);
                break;
        default:
                ret = -EINVAL;
                break;
        }

out:
        return ret;
}

static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
                                  union drm_wait_vblank *vblwait,
                                  struct drm_file *file_priv)
{
        struct drm_pending_vblank_event *e;
        struct timeval now;
        unsigned long flags;
        unsigned int seq;

        e = kzalloc(sizeof *e, GFP_KERNEL);
        if (e == NULL)
                return -ENOMEM;

        e->pipe = pipe;
        e->event.base.type = DRM_EVENT_VBLANK;
        e->event.base.length = sizeof e->event;
        e->event.user_data = vblwait->request.signal;
        e->base.event = &e->event.base;
        e->base.file_priv = file_priv;
        e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;

        do_gettimeofday(&now);
        spin_lock_irqsave(&dev->event_lock, flags);

        if (file_priv->event_space < sizeof e->event) {
                spin_unlock_irqrestore(&dev->event_lock, flags);
                kfree(e);
                return -ENOMEM;
        }

        file_priv->event_space -= sizeof e->event;
        seq = drm_vblank_count(dev, pipe);
        if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
            (seq - vblwait->request.sequence) <= (1 << 23)) {
                vblwait->request.sequence = seq + 1;
                vblwait->reply.sequence = vblwait->request.sequence;
        }

        DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
                  vblwait->request.sequence, seq, pipe);

        e->event.sequence = vblwait->request.sequence;
        if ((seq - vblwait->request.sequence) <= (1 << 23)) {
                e->event.tv_sec = now.tv_sec;
                e->event.tv_usec = now.tv_usec;
                drm_vblank_put(dev, e->pipe);
                list_add_tail(&e->base.link, &e->base.file_priv->event_list);
                wake_up_interruptible(&e->base.file_priv->event_wait);
        } else {
                list_add_tail(&e->base.link, &dev->vblank_event_list);
        }

        spin_unlock_irqrestore(&dev->event_lock, flags);

        return 0;
}

/**
 * Wait for VBLANK.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param data user argument, pointing to a drm_wait_vblank structure.
 * \return zero on success or a negative number on failure.
 *
 * 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
 * after a timeout with no further vblank waits scheduled).
 */
int drm_wait_vblank(struct drm_device *dev, void *data,
                    struct drm_file *file_priv)
{
        union drm_wait_vblank *vblwait = data;
        int ret = 0;
        unsigned int flags, seq, crtc;

        if ((!dev->pdev->irq) || (!dev->irq_enabled))
                return -EINVAL;

        if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
                return -EINVAL;

        if (vblwait->request.type &
            ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) {
                DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
                          vblwait->request.type,
                          (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK));
                return -EINVAL;
        }

        flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
        crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;

        if (crtc >= dev->num_crtcs)
                return -EINVAL;

        ret = drm_vblank_get(dev, crtc);
        if (ret) {
                DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
                return ret;
        }
        seq = drm_vblank_count(dev, crtc);

        switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
        case _DRM_VBLANK_RELATIVE:
                vblwait->request.sequence += seq;
                vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
        case _DRM_VBLANK_ABSOLUTE:
                break;
        default:
                ret = -EINVAL;
                goto done;
        }

        if (flags & _DRM_VBLANK_EVENT)
                return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);

        if ((flags & _DRM_VBLANK_NEXTONMISS) &&
            (seq - vblwait->request.sequence) <= (1<<23)) {
                vblwait->request.sequence = seq + 1;
        }

        DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
                  vblwait->request.sequence, crtc);
        dev->last_vblank_wait[crtc] = vblwait->request.sequence;
        DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
                    (((drm_vblank_count(dev, crtc) -
                       vblwait->request.sequence) <= (1 << 23)) ||
                     !dev->irq_enabled));

        if (ret != -EINTR) {
                struct timeval now;

                do_gettimeofday(&now);

                vblwait->reply.tval_sec = now.tv_sec;
                vblwait->reply.tval_usec = now.tv_usec;
                vblwait->reply.sequence = drm_vblank_count(dev, crtc);
                DRM_DEBUG("returning %d to client\n",
                          vblwait->reply.sequence);
        } else {
                DRM_DEBUG("vblank wait interrupted by signal\n");
        }

done:
        drm_vblank_put(dev, crtc);
        return ret;
}

void drm_handle_vblank_events(struct drm_device *dev, int crtc)
{
        struct drm_pending_vblank_event *e, *t;
        struct timeval now;
        unsigned long flags;
        unsigned int seq;

        do_gettimeofday(&now);
        seq = drm_vblank_count(dev, crtc);

        spin_lock_irqsave(&dev->event_lock, flags);

        list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
                if (e->pipe != crtc)
                        continue;
                if ((seq - e->event.sequence) > (1<<23))
                        continue;

                DRM_DEBUG("vblank event on %d, current %d\n",
                          e->event.sequence, seq);

                e->event.sequence = seq;
                e->event.tv_sec = now.tv_sec;
                e->event.tv_usec = now.tv_usec;
                drm_vblank_put(dev, e->pipe);
                list_move_tail(&e->base.link, &e->base.file_priv->event_list);
                wake_up_interruptible(&e->base.file_priv->event_wait);
        }

        spin_unlock_irqrestore(&dev->event_lock, flags);
}

/**
 * drm_handle_vblank - handle a vblank event
 * @dev: DRM device
 * @crtc: where this event occurred
 *
 * Drivers should call this routine in their vblank interrupt handlers to
 * update the vblank counter and send any signals that may be pending.
 */
void drm_handle_vblank(struct drm_device *dev, int crtc)
{
        if (!dev->num_crtcs)
                return;

        atomic_inc(&dev->_vblank_count[crtc]);
        DRM_WAKEUP(&dev->vbl_queue[crtc]);
        drm_handle_vblank_events(dev, crtc);
}
EXPORT_SYMBOL(drm_handle_vblank);