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 <tzimmermann@xxxxxxx> --- 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
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