1 files changed, 30 insertions, 16 deletions

diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
index 7ca486d750e9..bbc3bc4ba844 100644
--- a/drivers/gpu/drm/drm_debugfs_crc.c
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -46,10 +46,10 @@
  * it reached a given hardware component (a CRC sampling "source").
  *
  * Userspace can control generation of CRCs in a given CRTC by writing to the
- * file dri/0/crtc-N/crc/control in debugfs, with N being the index of the CRTC.
- * Accepted values are source names (which are driver-specific) and the "auto"
- * keyword, which will let the driver select a default source of frame CRCs
- * for this CRTC.
+ * file dri/0/crtc-N/crc/control in debugfs, with N being the :ref:`index of
+ * the CRTC<crtc_index>`. Accepted values are source names (which are
+ * driver-specific) and the "auto" keyword, which will let the driver select a
+ * default source of frame CRCs for this CRTC.
  *
  * Once frame CRC generation is enabled, userspace can capture them by reading
  * the dri/0/crtc-N/crc/data file. Each line in that file contains the frame
@@ -66,9 +66,18 @@
  * the reported CRCs of frames that should have the same contents.
  *
  * On the driver side the implementation effort is minimal, drivers only need to
- * implement &drm_crtc_funcs.set_crc_source. The debugfs files are automatically
- * set up if that vfunc is set. CRC samples need to be captured in the driver by
- * calling drm_crtc_add_crc_entry().
+ * implement &drm_crtc_funcs.set_crc_source and &drm_crtc_funcs.verify_crc_source.
+ * The debugfs files are automatically set up if those vfuncs are set. CRC samples
+ * need to be captured in the driver by calling drm_crtc_add_crc_entry().
+ * Depending on the driver and HW requirements, &drm_crtc_funcs.set_crc_source
+ * may result in a commit (even a full modeset).
+ *
+ * CRC results must be reliable across non-full-modeset atomic commits, so if a
+ * commit via DRM_IOCTL_MODE_ATOMIC would disable or otherwise interfere with
+ * CRC generation, then the driver must mark that commit as a full modeset
+ * (drm_atomic_crtc_needs_modeset() should return true). As a result, to ensure
+ * consistent results, generic userspace must re-setup CRC generation after a
+ * legacy SETCRTC or an atomic commit with DRM_MODE_ATOMIC_ALLOW_MODESET.
  */
 
 static int crc_control_show(struct seq_file *m, void *data)
@@ -131,12 +140,14 @@ static ssize_t crc_control_write(struct file *file, const char __user *ubuf,
 	if (IS_ERR(source))
 		return PTR_ERR(source);
 
-	if (source[len] == '\n')
-		source[len] = '\0';
+	if (source[len - 1] == '\n')
+		source[len - 1] = '\0';
 
 	ret = crtc->funcs->verify_crc_source(crtc, source, &values_cnt);
-	if (ret)
+	if (ret) {
+		kfree(source);
 		return ret;
+	}
 
 	spin_lock_irq(&crc->lock);
 
@@ -249,6 +260,11 @@ static int crtc_crc_release(struct inode *inode, struct file *filep)
 	struct drm_crtc *crtc = filep->f_inode->i_private;
 	struct drm_crtc_crc *crc = &crtc->crc;
 
+	/* terminate the infinite while loop if 'drm_dp_aux_crc_work' running */
+	spin_lock_irq(&crc->lock);
+	crc->opened = false;
+	spin_unlock_irq(&crc->lock);
+
 	crtc->funcs->set_crc_source(crtc, NULL);
 
 	spin_lock_irq(&crc->lock);
@@ -325,19 +341,17 @@ 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)
+static __poll_t 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_t ret = 0;
 
 	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;
+		ret |= EPOLLIN | EPOLLRDNORM;
 	spin_unlock_irq(&crc->lock);
 
 	return ret;
@@ -360,7 +374,7 @@ void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
 
 	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
 
-	debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
+	debugfs_create_file("control", S_IRUGO | S_IWUSR, crc_ent, crtc,
 			    &drm_crtc_crc_control_fops);
 	debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
 			    &drm_crtc_crc_data_fops);