[PATCH 1/2] drm/modeset: Handle tiled displays in pan_display_atomic.

[Maarten Lankhorst]

Tiled displays have a different x/y offset to begin with. Instead of
attempting to remember this, just apply a delta instead.

Hope this works..

Signed-off-by: Maarten Lankhorst <d...@lankhorst.se>
---
 drivers/gpu/drm/drm_fb_helper.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index c9008113111ba..fb3614a7ba44b 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1354,14 +1354,14 @@ int drm_fb_helper_set_par(struct fb_info *info)
 }
 EXPORT_SYMBOL(drm_fb_helper_set_par);
 
-static void pan_set(struct drm_fb_helper *fb_helper, int x, int y)
+static void pan_set(struct drm_fb_helper *fb_helper, int dx, int dy)
 {
        struct drm_mode_set *mode_set;
 
        mutex_lock(&fb_helper->client.modeset_mutex);
        drm_client_for_each_modeset(mode_set, &fb_helper->client) {
-               mode_set->x = x;
-               mode_set->y = y;
+               mode_set->x += dx;
+               mode_set->y += dy;
        }
        mutex_unlock(&fb_helper->client.modeset_mutex);
 }
@@ -1370,16 +1370,18 @@ static int pan_display_atomic(struct fb_var_screeninfo 
*var,
                              struct fb_info *info)
 {
        struct drm_fb_helper *fb_helper = info->par;
-       int ret;
+       int ret, dx, dy;
 
-       pan_set(fb_helper, var->xoffset, var->yoffset);
+       dx = var->xoffset - info->var.xoffset;
+       dy = var->yoffset - info->var.yoffset;
+       pan_set(fb_helper, dx, dy);
 
        ret = drm_client_modeset_commit_locked(&fb_helper->client);
        if (!ret) {
                info->var.xoffset = var->xoffset;
                info->var.yoffset = var->yoffset;
        } else
-               pan_set(fb_helper, info->var.xoffset, info->var.yoffset);
+               pan_set(fb_helper, -dx, -dy);
 
        return ret;
 }
-- 
2.43.0