[PATCH 16/21] drm/fb-helper: Call fb_sync in I/O functions

[Thomas Zimmermann]

Call struct fb_ops.fb_sync in drm_fbdev_{read,write}() to mimic the
behavior of fbdev. Fbdev implementations of fb_read and fb_write in
struct fb_ops invoke fb_sync to synchronize with outstanding operations
before I/O. Doing the same in DRM implementations will allow us to use
them throughout DRM drivers.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
 drivers/gpu/drm/drm_fb_helper.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index f6d22cc4cd876..379e0d2f67198 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2246,6 +2246,9 @@ static ssize_t drm_fbdev_fb_read(struct fb_info *info, char __user *buf,
 	if (total_size - count < pos)
 		count = total_size - pos;
 
+	if (info->fbops->fb_sync)
+		info->fbops->fb_sync(info);
+
 	if (drm_fbdev_use_iomem(info))
 		ret = fb_read_screen_base(info, buf, count, pos);
 	else
@@ -2327,6 +2330,9 @@ static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf,
 		count = total_size - pos;
 	}
 
+	if (info->fbops->fb_sync)
+		info->fbops->fb_sync(info);
+
 	/*
 	 * Copy to framebuffer even if we already logged an error. Emulates
 	 * the behavior of the original fbdev implementation.
-- 
2.38.0