[Intel-gfx] [PATCH] drm: Implement O_NONBLOCK support on /dev/dri/cardN
Chris Wilson
chris at chris-wilson.co.uk
Tue Oct 7 15:13:51 CEST 2014
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 at chris-wilson.co.uk>
Cc: dri-devel at 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);
--
2.1.1
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