[Intel-gfx] [PATCH v3 04/27] drm: Don't test for IRQ support in VBLANK ioctls

Thomas Zimmermann
2021-06-24T07:29:45Z

For KMS drivers, replace the IRQ check in VBLANK ioctls with a check for
vblank support. IRQs might be enabled wthout vblanking being supported.

This change also removes the DRM framework's only dependency on IRQ state
for non-legacy drivers. For legacy drivers with userspace modesetting,
the original test remains in drm_wait_vblank_ioctl().

v3:
* optimize test in drm_wait_vblank_ioctl() for KMS case (Liviu)
* update docs for drm_irq_uninstall()
v2:
* keep the old test for legacy drivers in
drm_wait_vblank_ioctl() (Daniel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/drm_irq.c | 13 ++++---------
drivers/gpu/drm/drm_vblank.c | 16 ++++++++++++----
2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index c3bd664ea733..945dd82e2ea3 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -74,10 +74,8 @@
* only supports devices with a single interrupt on the main device stored in
* &drm_device.dev and set as the device paramter in drm_dev_alloc().
*
- * These IRQ helpers are strictly optional. Drivers which roll their own only
- * need to set &drm_device.irq_enabled to signal the DRM core that vblank
- * interrupts are working. Since these helpers don't automatically clean up the
- * requested interrupt like e.g. devm_request_irq() they're not really
+ * These IRQ helpers are strictly optional. Since these helpers don't automatically
+ * clean up the requested interrupt like e.g. devm_request_irq() they're not really
* recommended.
*/

@@ -91,9 +89,7 @@
* 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.
+ * needs.
*
* @irq must match the interrupt number that would be passed to request_irq(),
* if called directly instead of using this helper function.
@@ -156,8 +152,7 @@ EXPORT_SYMBOL(drm_irq_install);
*
* Calls the driver's &drm_driver.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.
+ * to set up their interrupt handler.
*
* 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
diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 3417e1ac7918..10fe16bafcb6 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -1748,8 +1748,16 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
unsigned int pipe_index;
unsigned int flags, pipe, high_pipe;

- if (!dev->irq_enabled)
- return -EOPNOTSUPP;
+#if defined(CONFIG_DRM_LEGACY)
+ if (unlikely(drm_core_check_feature(dev, DRIVER_LEGACY))) {
+ if (!dev->irq_enabled)
+ return -EOPNOTSUPP;
+ } else /* if DRIVER_MODESET */
+#endif
+ {
+ if (!drm_dev_has_vblank(dev))
+ return -EOPNOTSUPP;
+ }

if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
return -EINVAL;
@@ -2023,7 +2031,7 @@ int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data,
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EOPNOTSUPP;

- if (!dev->irq_enabled)
+ if (!drm_dev_has_vblank(dev))
return -EOPNOTSUPP;

crtc = drm_crtc_find(dev, file_priv, get_seq->crtc_id);
@@ -2082,7 +2090,7 @@ int drm_crtc_queue_sequence_ioctl(struct drm_device *dev, void *data,
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EOPNOTSUPP;

- if (!dev->irq_enabled)
+ if (!drm_dev_has_vblank(dev))
return -EOPNOTSUPP;

crtc = drm_crtc_find(dev, file_priv, queue_seq->crtc_id);