drm/crc: Only report a single overflow when a CRC fd is opened

This reduces the amount of spam when you debug a CRC reading
program.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[mlankhorst: Change bool overflow to was_overflow (Ville)]
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180418125121.72081-1-maarten.lankhorst@linux.intel.com

diff --git a/drivers/gpu/drm/drm_debugfs_crc.c b/drivers/gpu/drm/drm_debugfs_crc.c
index 9f83121..9996119 100644 (file)
--- a/drivers/gpu/drm/drm_debugfs_crc.c
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -139,6 +139,7 @@ static int crtc_crc_data_count(struct drm_crtc_crc *crc)
 static void crtc_crc_cleanup(struct drm_crtc_crc *crc)
 {
        kfree(crc->entries);
+       crc->overflow = false;
        crc->entries = NULL;
        crc->head = 0;
        crc->tail = 0;
@@ -391,8 +392,14 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame,
        tail = crc->tail;
 
        if (CIRC_SPACE(head, tail, DRM_CRC_ENTRIES_NR) < 1) {
+               bool was_overflow = crc->overflow;
+
+               crc->overflow = true;
                spin_unlock(&crc->lock);
-               DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");
+
+               if (!was_overflow)
+                       DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");
+
                return -ENOBUFS;
        }
 

diff --git a/include/drm/drm_debugfs_crc.h b/include/drm/drm_debugfs_crc.h
index 7d63b1d..b225eeb 100644 (file)
--- a/include/drm/drm_debugfs_crc.h
+++ b/include/drm/drm_debugfs_crc.h
@@ -43,6 +43,7 @@ struct drm_crtc_crc_entry {
  * @lock: protects the fields in this struct
  * @source: name of the currently configured source of CRCs
  * @opened: whether userspace has opened the data file for reading
+ * @overflow: whether an overflow occured.
  * @entries: array of entries, with size of %DRM_CRC_ENTRIES_NR
  * @head: head of circular queue
  * @tail: tail of circular queue
@@ -52,7 +53,7 @@ struct drm_crtc_crc_entry {
 struct drm_crtc_crc {
        spinlock_t lock;
        const char *source;
-       bool opened;
+       bool opened, overflow;
        struct drm_crtc_crc_entry *entries;
        int head, tail;
        size_t values_cnt;