Hi Liviu Am 22.06.21 um 17:25 schrieb Liviu Dudau: > Hello, > > On Tue, Jun 22, 2021 at 04:09:44PM +0200, Thomas Zimmermann wrote: >> 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(). >> >> v2: >> * keep the old test for legacy drivers in >> drm_wait_vblank_ioctl() (Daniel) >> >> Signed-off-by: Thomas Zimmermann >> --- >> drivers/gpu/drm/drm_irq.c | 10 +++------- >> drivers/gpu/drm/drm_vblank.c | 13 +++++++++---- >> 2 files changed, 12 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c >> index c3bd664ea733..1d7785721323 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. >> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c >> index 3417e1ac7918..a98a4aad5037 100644 >> --- a/drivers/gpu/drm/drm_vblank.c >> +++ b/drivers/gpu/drm/drm_vblank.c >> @@ -1748,8 +1748,13 @@ 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 (drm_core_check_feature(dev, DRIVER_MODESET)) { >> + if (!drm_dev_has_vblank(dev)) >> + return -EOPNOTSUPP; >> + } else { >> + if (!dev->irq_enabled) >> + return -EOPNOTSUPP; >> + } > > For a system call that is used quite a lot by userspace we have increased the code size > in a noticeable way. Can we not cache it privately? I'm not quite sure that I understand your concern. The additionally called functions are trivial one-liners; probably inlined anyway. However, irq_enabled is only relevant for legacy drivers and will eventually disappear behind CONFIG_DRM_LEGACY. We can rewrite the test like this: ifdef CONFIG_DRM_LEGACY if (unlikely(check_feature(dev, DRIVER_LEGACY))) { if (!irq_enabled) return; } else #endif { if (!has_vblank_support(dev)) return; } As CONFIG_DRM_LEGACY is most likely disabled on concurrent systems, we'd get a single test for the modern drivers. If DRM_LEGACYis on, the compiler at least knows that the else branch is preferred. Best regards Thomas -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer