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drm/crc: Add support for polling on the data fd. 

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]
This commit is contained in:
Maarten Lankhorst 2018-02-02 15:27:43 +01:00
parent bc4fde30e5
commit 4beb3b40ae
1 changed files with 19 additions and 0 deletions
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19
drivers/gpu/drm/drm_debugfs_crc.c
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@ -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,
};