linux/drivers/gpu/drm/drm_irq.c

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/*
* drm_irq.c IRQ and vblank support
*
* \author Rickard E. (Rik) Faith <faith@valinux.com>
* \author Gareth Hughes <gareth@valinux.com>
*
* 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.
*/
/*
* 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 <drm/drm_irq.h>
#include <drm/drmP.h>
#include <linux/interrupt.h> /* For task queue support */
#include <linux/vgaarb.h>
#include <linux/export.h>
drm/vblank: Add support for precise vblank timestamping. The DRI2 swap & sync implementation needs precise vblank counts and precise timestamps corresponding to those vblank counts. For conformance to the OpenML OML_sync_control extension specification the DRM timestamp associated with a vblank count should correspond to the start of video scanout of the first scanline of the video frame following the vblank interval for that vblank count. Therefore we need to carry around precise timestamps for vblanks. Currently the DRM and KMS drivers generate timestamps ad-hoc via do_gettimeofday() in some places. The resulting timestamps are sometimes not very precise due to interrupt handling delays, they don't conform to OML_sync_control and some are wrong, as they aren't taken synchronized to the vblank. This patch implements support inside the drm core for precise and robust timestamping. It consists of the following interrelated pieces. 1. Vblank timestamp caching: A per-crtc ringbuffer stores the most recent vblank timestamps corresponding to vblank counts. The ringbuffer can be read out lock-free via the accessor function: struct timeval timestamp; vblankcount = drm_vblank_count_and_time(dev, crtcid, &timestamp). The function returns the current vblank count and the corresponding timestamp for start of video scanout following the vblank interval. It can be used anywhere between enclosing drm_vblank_get(dev, crtcid) and drm_vblank_put(dev,crtcid) statements. It is used inside the drmWaitVblank ioctl and in the vblank event queueing and handling. It should be used by kms drivers for timestamping of bufferswap completion. The timestamp ringbuffer is reinitialized each time vblank irq's get reenabled in drm_vblank_get()/ drm_update_vblank_count(). It is invalidated when vblank irq's get disabled. The ringbuffer is updated inside drm_handle_vblank() at each vblank irq. 2. Calculation of precise vblank timestamps: drm_get_last_vbltimestamp() is used to compute the timestamp for the end of the most recent vblank (if inside active scanout), or the expected end of the current vblank interval (if called inside a vblank interval). The function calls into a new optional kms driver entry point dev->driver->get_vblank_timestamp() which is supposed to provide the precise timestamp. If a kms driver doesn't implement the entry point or if the call fails, a simple do_gettimeofday() timestamp is returned as crude approximation of the true vblank time. A new drm module parameter drm.timestamp_precision_usec allows to disable high precision timestamps (if set to zero) or to specify the maximum acceptable error in the timestamps in microseconds. Kms drivers could implement their get_vblank_timestamp() function in a gpu specific way, as long as returned timestamps conform to OML_sync_control, e.g., by use of gpu specific hardware timestamps. Optionally, kms drivers can simply wrap and use the new utility function drm_calc_vbltimestamp_from_scanoutpos(). This function calls a new optional kms driver function dev->driver->get_scanout_position() which returns the current horizontal and vertical video scanout position of the crtc. The scanout position together with the drm_display_timing of the current video mode is used to calculate elapsed time relative to start of active scanout for the current video frame. This elapsed time is subtracted from the current do_gettimeofday() time to get the timestamp corresponding to start of video scanout. Currently non-interlaced, non-doublescan video modes, with or without panel scaling are handled correctly. Interlaced/ doublescan modes are tbd in a future patch. 3. Filtering of redundant vblank irq's and removal of some race-conditions in the vblank irq enable/disable path: Some gpu's (e.g., Radeon R500/R600) send spurious vblank irq's outside the vblank if vblank irq's get reenabled. These get detected by use of the vblank timestamps and filtered out to avoid miscounting of vblanks. Some race-conditions between the vblank irq enable/disable functions, the vblank irq handler and the gpu itself (updating its hardware vblank counter in the "wrong" moment) are fixed inside vblank_disable_and_save() and drm_update_vblank_count() by use of the vblank timestamps and a new spinlock dev->vblank_time_lock. The time until vblank irq disable is now configurable via a new drm module parameter drm.vblankoffdelay to allow experimentation with timeouts that are much shorter than the current 5 seconds and should allow longer vblank off periods for better power savings. Followup patches will use these new functions to implement precise timestamping for the intel and radeon kms drivers. Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de> Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-10-23 10:20:23 +08:00
#include "drm_internal.h"
/**
* 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
* 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)
{
int ret;
unsigned long sh_flags = 0;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
if (irq == 0)
return -EINVAL;
/* Driver must have been initialized */
if (!dev->dev_private)
return -EINVAL;
if (dev->irq_enabled)
return -EBUSY;
dev->irq_enabled = true;
DRM_DEBUG("irq=%d\n", irq);
/* Before installing handler */
if (dev->driver->irq_preinstall)
dev->driver->irq_preinstall(dev);
/* Install handler */
if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
sh_flags = IRQF_SHARED;
ret = request_irq(irq, dev->driver->irq_handler,
sh_flags, dev->driver->name, dev);
if (ret < 0) {
dev->irq_enabled = false;
return ret;
}
/* After installing handler */
if (dev->driver->irq_postinstall)
ret = dev->driver->irq_postinstall(dev);
if (ret < 0) {
dev->irq_enabled = false;
if (drm_core_check_feature(dev, DRIVER_LEGACY))
vga_client_register(dev->pdev, NULL, NULL, NULL);
free_irq(irq, dev);
} else {
dev->irq = irq;
}
return ret;
}
EXPORT_SYMBOL(drm_irq_install);
/**
* 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.
*
* 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.
*
* Returns:
* Zero on success or a negative error code on failure.
*/
drm/vblank: Add support for precise vblank timestamping. The DRI2 swap & sync implementation needs precise vblank counts and precise timestamps corresponding to those vblank counts. For conformance to the OpenML OML_sync_control extension specification the DRM timestamp associated with a vblank count should correspond to the start of video scanout of the first scanline of the video frame following the vblank interval for that vblank count. Therefore we need to carry around precise timestamps for vblanks. Currently the DRM and KMS drivers generate timestamps ad-hoc via do_gettimeofday() in some places. The resulting timestamps are sometimes not very precise due to interrupt handling delays, they don't conform to OML_sync_control and some are wrong, as they aren't taken synchronized to the vblank. This patch implements support inside the drm core for precise and robust timestamping. It consists of the following interrelated pieces. 1. Vblank timestamp caching: A per-crtc ringbuffer stores the most recent vblank timestamps corresponding to vblank counts. The ringbuffer can be read out lock-free via the accessor function: struct timeval timestamp; vblankcount = drm_vblank_count_and_time(dev, crtcid, &timestamp). The function returns the current vblank count and the corresponding timestamp for start of video scanout following the vblank interval. It can be used anywhere between enclosing drm_vblank_get(dev, crtcid) and drm_vblank_put(dev,crtcid) statements. It is used inside the drmWaitVblank ioctl and in the vblank event queueing and handling. It should be used by kms drivers for timestamping of bufferswap completion. The timestamp ringbuffer is reinitialized each time vblank irq's get reenabled in drm_vblank_get()/ drm_update_vblank_count(). It is invalidated when vblank irq's get disabled. The ringbuffer is updated inside drm_handle_vblank() at each vblank irq. 2. Calculation of precise vblank timestamps: drm_get_last_vbltimestamp() is used to compute the timestamp for the end of the most recent vblank (if inside active scanout), or the expected end of the current vblank interval (if called inside a vblank interval). The function calls into a new optional kms driver entry point dev->driver->get_vblank_timestamp() which is supposed to provide the precise timestamp. If a kms driver doesn't implement the entry point or if the call fails, a simple do_gettimeofday() timestamp is returned as crude approximation of the true vblank time. A new drm module parameter drm.timestamp_precision_usec allows to disable high precision timestamps (if set to zero) or to specify the maximum acceptable error in the timestamps in microseconds. Kms drivers could implement their get_vblank_timestamp() function in a gpu specific way, as long as returned timestamps conform to OML_sync_control, e.g., by use of gpu specific hardware timestamps. Optionally, kms drivers can simply wrap and use the new utility function drm_calc_vbltimestamp_from_scanoutpos(). This function calls a new optional kms driver function dev->driver->get_scanout_position() which returns the current horizontal and vertical video scanout position of the crtc. The scanout position together with the drm_display_timing of the current video mode is used to calculate elapsed time relative to start of active scanout for the current video frame. This elapsed time is subtracted from the current do_gettimeofday() time to get the timestamp corresponding to start of video scanout. Currently non-interlaced, non-doublescan video modes, with or without panel scaling are handled correctly. Interlaced/ doublescan modes are tbd in a future patch. 3. Filtering of redundant vblank irq's and removal of some race-conditions in the vblank irq enable/disable path: Some gpu's (e.g., Radeon R500/R600) send spurious vblank irq's outside the vblank if vblank irq's get reenabled. These get detected by use of the vblank timestamps and filtered out to avoid miscounting of vblanks. Some race-conditions between the vblank irq enable/disable functions, the vblank irq handler and the gpu itself (updating its hardware vblank counter in the "wrong" moment) are fixed inside vblank_disable_and_save() and drm_update_vblank_count() by use of the vblank timestamps and a new spinlock dev->vblank_time_lock. The time until vblank irq disable is now configurable via a new drm module parameter drm.vblankoffdelay to allow experimentation with timeouts that are much shorter than the current 5 seconds and should allow longer vblank off periods for better power savings. Followup patches will use these new functions to implement precise timestamping for the intel and radeon kms drivers. Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de> Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-10-23 10:20:23 +08:00
int drm_irq_uninstall(struct drm_device *dev)
{
unsigned long irqflags;
bool irq_enabled;
int i;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
irq_enabled = dev->irq_enabled;
dev->irq_enabled = false;
/*
drm/irq: Don't call ->get_vblank_counter directly from irq_uninstall/cleanup The pipe might already have been shut down, and then it's not a good idea to call hw accessor functions. Instead use the same logic as drm_vblank_off which has all the necessary checks to avoid troubles or inconsistency. Noticed by Imre while reviewing my patches to remove some sanity checks from ->get_vblank_counter. v2: Try harder. disable_and_save can still access the vblank stuff when vblank->enabled isn't set. It has to, since vlbank irq could be disable but the pipe is still on when being called from drm_vblank_off. But we still want to use that code for more code sharing. So add a check for vblank->enabled on top - if that's not set we shouldn't have anyone waiting for the vblank. If we have that's a pretty serious bug. The other issue that Imre spotted is drm_vblank_cleanup. That code again calls disable_and_save and so suffers from the same issues. But really drm_irq_uninstall should have cleaned that all up, so replace the code with WARN_ON. Note that we can't delete the timer cleanup since drivers aren't required to use drm_irq_install/uninstall, but can do their own irq handling. v3: Make it clear that all that gunk in drm_irq_uninstall is really just bandaids for UMS races between the irq/vblank code. In UMS userspace is in control of enabling/disabling interrupts in general and vblanks specifically. v4: Imre observed that KMS drivers all call drm_vblank_cleanup before drm_irq_uninstall (as they should), so again the code in there is dead for KMS (due to dev->num_crtcs == 0 after drm_vblank_cleanup). Or should be, so only WARN for KMS - with UMS userspace could try to do evil things. v5: After more discussion on irc we've gone back to v3: the del_timer_sync is required in all cases in drm_vblank_cleanup, but let's restrict the WARN_ON to kms drivers only. Imre was also concerned that bad things could happen without the disable_and_save call. But we immediately free vblank structures afterwards which makes the save useless. And drm_handle_vblank has a check for dev->num_crtcs to avoid surprises with ums. Cc: Imre Deak <imre.deak@intel.com> Reviewed-by: Imre Deak <imre.deak@intel.com> Acked-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-02-22 22:11:19 +08:00
* Wake up any waiters so they don't hang. This is just to paper over
* issues for UMS drivers which aren't in full control of their
drm/irq: Don't call ->get_vblank_counter directly from irq_uninstall/cleanup The pipe might already have been shut down, and then it's not a good idea to call hw accessor functions. Instead use the same logic as drm_vblank_off which has all the necessary checks to avoid troubles or inconsistency. Noticed by Imre while reviewing my patches to remove some sanity checks from ->get_vblank_counter. v2: Try harder. disable_and_save can still access the vblank stuff when vblank->enabled isn't set. It has to, since vlbank irq could be disable but the pipe is still on when being called from drm_vblank_off. But we still want to use that code for more code sharing. So add a check for vblank->enabled on top - if that's not set we shouldn't have anyone waiting for the vblank. If we have that's a pretty serious bug. The other issue that Imre spotted is drm_vblank_cleanup. That code again calls disable_and_save and so suffers from the same issues. But really drm_irq_uninstall should have cleaned that all up, so replace the code with WARN_ON. Note that we can't delete the timer cleanup since drivers aren't required to use drm_irq_install/uninstall, but can do their own irq handling. v3: Make it clear that all that gunk in drm_irq_uninstall is really just bandaids for UMS races between the irq/vblank code. In UMS userspace is in control of enabling/disabling interrupts in general and vblanks specifically. v4: Imre observed that KMS drivers all call drm_vblank_cleanup before drm_irq_uninstall (as they should), so again the code in there is dead for KMS (due to dev->num_crtcs == 0 after drm_vblank_cleanup). Or should be, so only WARN for KMS - with UMS userspace could try to do evil things. v5: After more discussion on irc we've gone back to v3: the del_timer_sync is required in all cases in drm_vblank_cleanup, but let's restrict the WARN_ON to kms drivers only. Imre was also concerned that bad things could happen without the disable_and_save call. But we immediately free vblank structures afterwards which makes the save useless. And drm_handle_vblank has a check for dev->num_crtcs to avoid surprises with ums. Cc: Imre Deak <imre.deak@intel.com> Reviewed-by: Imre Deak <imre.deak@intel.com> Acked-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-02-22 22:11:19 +08:00
* vblank/irq handling. KMS drivers must ensure that vblanks are all
* disabled when uninstalling the irq handler.
*/
if (dev->num_crtcs) {
spin_lock_irqsave(&dev->vbl_lock, irqflags);
for (i = 0; i < dev->num_crtcs; i++) {
struct drm_vblank_crtc *vblank = &dev->vblank[i];
drm/irq: Don't call ->get_vblank_counter directly from irq_uninstall/cleanup The pipe might already have been shut down, and then it's not a good idea to call hw accessor functions. Instead use the same logic as drm_vblank_off which has all the necessary checks to avoid troubles or inconsistency. Noticed by Imre while reviewing my patches to remove some sanity checks from ->get_vblank_counter. v2: Try harder. disable_and_save can still access the vblank stuff when vblank->enabled isn't set. It has to, since vlbank irq could be disable but the pipe is still on when being called from drm_vblank_off. But we still want to use that code for more code sharing. So add a check for vblank->enabled on top - if that's not set we shouldn't have anyone waiting for the vblank. If we have that's a pretty serious bug. The other issue that Imre spotted is drm_vblank_cleanup. That code again calls disable_and_save and so suffers from the same issues. But really drm_irq_uninstall should have cleaned that all up, so replace the code with WARN_ON. Note that we can't delete the timer cleanup since drivers aren't required to use drm_irq_install/uninstall, but can do their own irq handling. v3: Make it clear that all that gunk in drm_irq_uninstall is really just bandaids for UMS races between the irq/vblank code. In UMS userspace is in control of enabling/disabling interrupts in general and vblanks specifically. v4: Imre observed that KMS drivers all call drm_vblank_cleanup before drm_irq_uninstall (as they should), so again the code in there is dead for KMS (due to dev->num_crtcs == 0 after drm_vblank_cleanup). Or should be, so only WARN for KMS - with UMS userspace could try to do evil things. v5: After more discussion on irc we've gone back to v3: the del_timer_sync is required in all cases in drm_vblank_cleanup, but let's restrict the WARN_ON to kms drivers only. Imre was also concerned that bad things could happen without the disable_and_save call. But we immediately free vblank structures afterwards which makes the save useless. And drm_handle_vblank has a check for dev->num_crtcs to avoid surprises with ums. Cc: Imre Deak <imre.deak@intel.com> Reviewed-by: Imre Deak <imre.deak@intel.com> Acked-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
2015-02-22 22:11:19 +08:00
if (!vblank->enabled)
continue;
WARN_ON(drm_core_check_feature(dev, DRIVER_MODESET));
drm_vblank_disable_and_save(dev, i);
wake_up(&vblank->queue);
}
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
if (!irq_enabled)
return -EINVAL;
DRM_DEBUG("irq=%d\n", dev->irq);
if (drm_core_check_feature(dev, DRIVER_LEGACY))
vga_client_register(dev->pdev, NULL, NULL, NULL);
if (dev->driver->irq_uninstall)
dev->driver->irq_uninstall(dev);
free_irq(dev->irq, dev);
return 0;
}
EXPORT_SYMBOL(drm_irq_uninstall);
int drm_legacy_irq_control(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_control *ctl = data;
int ret = 0, irq;
drm/vblank: Add support for precise vblank timestamping. The DRI2 swap & sync implementation needs precise vblank counts and precise timestamps corresponding to those vblank counts. For conformance to the OpenML OML_sync_control extension specification the DRM timestamp associated with a vblank count should correspond to the start of video scanout of the first scanline of the video frame following the vblank interval for that vblank count. Therefore we need to carry around precise timestamps for vblanks. Currently the DRM and KMS drivers generate timestamps ad-hoc via do_gettimeofday() in some places. The resulting timestamps are sometimes not very precise due to interrupt handling delays, they don't conform to OML_sync_control and some are wrong, as they aren't taken synchronized to the vblank. This patch implements support inside the drm core for precise and robust timestamping. It consists of the following interrelated pieces. 1. Vblank timestamp caching: A per-crtc ringbuffer stores the most recent vblank timestamps corresponding to vblank counts. The ringbuffer can be read out lock-free via the accessor function: struct timeval timestamp; vblankcount = drm_vblank_count_and_time(dev, crtcid, &timestamp). The function returns the current vblank count and the corresponding timestamp for start of video scanout following the vblank interval. It can be used anywhere between enclosing drm_vblank_get(dev, crtcid) and drm_vblank_put(dev,crtcid) statements. It is used inside the drmWaitVblank ioctl and in the vblank event queueing and handling. It should be used by kms drivers for timestamping of bufferswap completion. The timestamp ringbuffer is reinitialized each time vblank irq's get reenabled in drm_vblank_get()/ drm_update_vblank_count(). It is invalidated when vblank irq's get disabled. The ringbuffer is updated inside drm_handle_vblank() at each vblank irq. 2. Calculation of precise vblank timestamps: drm_get_last_vbltimestamp() is used to compute the timestamp for the end of the most recent vblank (if inside active scanout), or the expected end of the current vblank interval (if called inside a vblank interval). The function calls into a new optional kms driver entry point dev->driver->get_vblank_timestamp() which is supposed to provide the precise timestamp. If a kms driver doesn't implement the entry point or if the call fails, a simple do_gettimeofday() timestamp is returned as crude approximation of the true vblank time. A new drm module parameter drm.timestamp_precision_usec allows to disable high precision timestamps (if set to zero) or to specify the maximum acceptable error in the timestamps in microseconds. Kms drivers could implement their get_vblank_timestamp() function in a gpu specific way, as long as returned timestamps conform to OML_sync_control, e.g., by use of gpu specific hardware timestamps. Optionally, kms drivers can simply wrap and use the new utility function drm_calc_vbltimestamp_from_scanoutpos(). This function calls a new optional kms driver function dev->driver->get_scanout_position() which returns the current horizontal and vertical video scanout position of the crtc. The scanout position together with the drm_display_timing of the current video mode is used to calculate elapsed time relative to start of active scanout for the current video frame. This elapsed time is subtracted from the current do_gettimeofday() time to get the timestamp corresponding to start of video scanout. Currently non-interlaced, non-doublescan video modes, with or without panel scaling are handled correctly. Interlaced/ doublescan modes are tbd in a future patch. 3. Filtering of redundant vblank irq's and removal of some race-conditions in the vblank irq enable/disable path: Some gpu's (e.g., Radeon R500/R600) send spurious vblank irq's outside the vblank if vblank irq's get reenabled. These get detected by use of the vblank timestamps and filtered out to avoid miscounting of vblanks. Some race-conditions between the vblank irq enable/disable functions, the vblank irq handler and the gpu itself (updating its hardware vblank counter in the "wrong" moment) are fixed inside vblank_disable_and_save() and drm_update_vblank_count() by use of the vblank timestamps and a new spinlock dev->vblank_time_lock. The time until vblank irq disable is now configurable via a new drm module parameter drm.vblankoffdelay to allow experimentation with timeouts that are much shorter than the current 5 seconds and should allow longer vblank off periods for better power savings. Followup patches will use these new functions to implement precise timestamping for the intel and radeon kms drivers. Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de> Signed-off-by: Dave Airlie <airlied@redhat.com>
2010-10-23 10:20:23 +08:00
/* if we haven't irq we fallback for compatibility reasons -
* this used to be a separate function in drm_dma.h
*/
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return 0;
if (!drm_core_check_feature(dev, DRIVER_LEGACY))
return 0;
/* UMS was only ever supported on pci devices. */
if (WARN_ON(!dev->pdev))
return -EINVAL;
switch (ctl->func) {
case DRM_INST_HANDLER:
irq = dev->pdev->irq;
if (dev->if_version < DRM_IF_VERSION(1, 2) &&
ctl->irq != irq)
return -EINVAL;
mutex_lock(&dev->struct_mutex);
ret = drm_irq_install(dev, irq);
mutex_unlock(&dev->struct_mutex);
return ret;
case DRM_UNINST_HANDLER:
mutex_lock(&dev->struct_mutex);
ret = drm_irq_uninstall(dev);
mutex_unlock(&dev->struct_mutex);
return ret;
default:
return -EINVAL;
}
}