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

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

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@xxxxxxx>
---
 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