Commit bd008e5b authored Oct 07, 2014 by Chris Wilson Committed by Daniel Vetter Oct 08, 2014

drm: Implement O_NONBLOCK support on /dev/dri/cardN



The implmentation is simple in the extreme: we only want to wait for
events if the device was opened in blocking mode, otherwise we grab what
is available and report an error if there was none.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Testcase: igt/kms_flip/nonblocing_read
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

parent 1bcecfac

drivers/gpu/drm/drm_fops.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -515,10 +515,12 @@ ssize_t drm_read(struct file filp, char __user buffer,
		size_t total;
		ssize_t ret;

		if ((filp->f_flags & O_NONBLOCK) == 0) {
		ret = wait_event_interruptible(file_priv->event_wait,
		!list_empty(&file_priv->event_list));
		if (ret < 0)
		return ret;
		}

		total = 0;
		while (drm_dequeue_event(file_priv, total, count, &e)) {
		@@ -532,7 +534,7 @@ ssize_t drm_read(struct file filp, char __user buffer,
		e->destroy(e);
		}

		return total;
		return total ?: -EAGAIN;
		}
		EXPORT_SYMBOL(drm_read);