From 4beb3b40ae7f994af01200323441df13f8f5b241 Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date: Fri, 2 Feb 2018 15:27:43 +0100
Subject: [PATCH] drm/crc: Add support for polling on the data fd.
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This will make it possible for userspace to know whether reading
will block, without blocking on the fd. This makes it possible to
drain all queued CRC's in blocking mode, without having to reopen
the fd.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180202142743.68527-1-maarten.lankhorst@linux.intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[mlankhorst: Use POLLIN|POLLRDNORM, based on Ville's suggestion]
---
drivers/gpu/drm/drm_debugfs_crc.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
index 9dd879589a2c5..9f8312137cade 100644
--- a/drivers/gpu/drm/drm_debugfs_crc.c
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -307,10 +307,29 @@ static ssize_t crtc_crc_read(struct file *filep, char __user *user_buf,
return LINE_LEN(crc->values_cnt);
}
+static unsigned int crtc_crc_poll(struct file *file, poll_table *wait)
+{
+ struct drm_crtc *crtc = file->f_inode->i_private;
+ struct drm_crtc_crc *crc = &crtc->crc;
+ unsigned ret;
+
+ poll_wait(file, &crc->wq, wait);
+
+ spin_lock_irq(&crc->lock);
+ if (crc->source && crtc_crc_data_count(crc))
+ ret = POLLIN | POLLRDNORM;
+ else
+ ret = 0;
+ spin_unlock_irq(&crc->lock);
+
+ return ret;
+}
+
static const struct file_operations drm_crtc_crc_data_fops = {
.owner = THIS_MODULE,
.open = crtc_crc_open,
.read = crtc_crc_read,
+ .poll = crtc_crc_poll,
.release = crtc_crc_release,
};
--
2.30.2