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 --- drivers/gpu/drm/drm_fops.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index ed7bc68f7e87..91e1105f2800 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -515,10 +515,12 @@ ssize_t drm_read(struct file *filp, char __user *buffer, size_t total; ssize_t ret;
- ret = wait_event_interruptible(file_priv->event_wait, - !list_empty(&file_priv->event_list)); - if (ret < 0) - return 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);