1 files changed, 35 insertions, 34 deletions

diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
index 00e743153e94..ca3c55c6b815 100644
--- a/drivers/gpu/drm/drm_debugfs_crc.c
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -29,7 +29,14 @@
 #include <linux/circ_buf.h>
 #include <linux/ctype.h>
 #include <linux/debugfs.h>
-#include <drm/drmP.h>
+#include <linux/poll.h>
+#include <linux/uaccess.h>
+
+#include <drm/drm_crtc.h>
+#include <drm/drm_debugfs_crc.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_print.h>
+
 #include "drm_internal.h"
 
 /**
@@ -59,9 +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)
@@ -318,19 +334,17 @@ 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;
@@ -344,33 +358,19 @@ static const struct file_operations drm_crtc_crc_data_fops = {
 	.release = crtc_crc_release,
 };
 
-int drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
+void drm_debugfs_crtc_crc_add(struct drm_crtc *crtc)
 {
-	struct dentry *crc_ent, *ent;
+	struct dentry *crc_ent;
 
 	if (!crtc->funcs->set_crc_source || !crtc->funcs->verify_crc_source)
-		return 0;
+		return;
 
 	crc_ent = debugfs_create_dir("crc", crtc->debugfs_entry);
-	if (!crc_ent)
-		return -ENOMEM;
-
-	ent = debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
-				  &drm_crtc_crc_control_fops);
-	if (!ent)
-		goto error;
-
-	ent = debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
-				  &drm_crtc_crc_data_fops);
-	if (!ent)
-		goto error;
-
-	return 0;
-
-error:
-	debugfs_remove_recursive(crc_ent);
 
-	return -ENOMEM;
+	debugfs_create_file("control", S_IRUGO, crc_ent, crtc,
+			    &drm_crtc_crc_control_fops);
+	debugfs_create_file("data", S_IRUGO, crc_ent, crtc,
+			    &drm_crtc_crc_data_fops);
 }
 
 /**
@@ -389,12 +389,13 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
 	struct drm_crtc_crc *crc = &crtc->crc;
 	struct drm_crtc_crc_entry *entry;
 	int head, tail;
+	unsigned long flags;
 
-	spin_lock(&crc->lock);
+	spin_lock_irqsave(&crc->lock, flags);
 
 	/* Caller may not have noticed yet that userspace has stopped reading */
 	if (!crc->entries) {
-		spin_unlock(&crc->lock);
+		spin_unlock_irqrestore(&crc->lock, flags);
 		return -EINVAL;
 	}
 
@@ -405,7 +406,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
 		bool was_overflow = crc->overflow;
 
 		crc->overflow = true;
-		spin_unlock(&crc->lock);
+		spin_unlock_irqrestore(&crc->lock, flags);
 
 		if (!was_overflow)
 			DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");
@@ -421,7 +422,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
 	head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);
 	crc->head = head;
 
-	spin_unlock(&crc->lock);
+	spin_unlock_irqrestore(&crc->lock, flags);
 
 	wake_up_interruptible(&crc->wq);