3 files changed, 87 insertions, 0 deletions

diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
index 6fc3501581d6..34899bd7c9f3 100644
--- a/drivers/video/console/fbcon.c
+++ b/drivers/video/console/fbcon.c
@@ -3043,6 +3043,43 @@ static void fbcon_new_modelist(struct fb_info *info)
         }
 }
 
+static void fbcon_get_requirement(struct fb_info *info,
+                                  struct fb_blit_caps *caps)
+{
+        struct vc_data *vc;
+        struct display *p;
+        int charcnt;
+
+        if (caps->flags) {
+                int i;
+
+                for (i = first_fb_vc; i <= last_fb_vc; i++) {
+                        vc = vc_cons[i].d;
+                        if (vc && vc->vc_mode == KD_TEXT) {
+                                p = &fb_display[i];
+                                caps->x |= 1 << (vc->vc_font.width - 1);
+                                caps->y |= 1 << (vc->vc_font.height - 1);
+                                charcnt = (p->userfont) ?
+                                        FNTCHARCNT(p->fontdata) : 256;
+                                if (caps->len < charcnt)
+                                        caps->len = charcnt;
+                        }
+                }
+        } else {
+                vc = vc_cons[fg_console].d;
+
+                if (vc && vc->vc_mode == KD_TEXT) {
+                        p = &fb_display[fg_console];
+                        caps->x |= 1 << (vc->vc_font.width - 1);
+                        caps->y |= 1 << (vc->vc_font.height - 1);
+                        charcnt = (p->userfont) ?
+                                FNTCHARCNT(p->fontdata) : 256;
+                        if (caps->len < charcnt)
+                                caps->len = charcnt;
+                }
+        }
+}
+
 static int fbcon_event_notify(struct notifier_block *self, 
                               unsigned long action, void *data)
 {
@@ -3050,6 +3087,7 @@ static int fbcon_event_notify(struct notifier_block *self,
         struct fb_info *info = event->info;
         struct fb_videomode *mode;
         struct fb_con2fbmap *con2fb;
+        struct fb_blit_caps *caps;
         int ret = 0;
 
         /*
@@ -3098,6 +3136,10 @@ static int fbcon_event_notify(struct notifier_block *self,
         case FB_EVENT_NEW_MODELIST:
                 fbcon_new_modelist(info);
                 break;
+        case FB_EVENT_GET_REQ:
+                caps = event->data;
+                fbcon_get_requirement(info, caps);
+                break;
         }
 
 done:
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index cd1407921af5..354711c84aaa 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -773,6 +773,29 @@ fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
         return 0;
 }
 
+static int fb_check_caps(struct fb_info *info, struct fb_var_screeninfo *var,
+                         u32 activate)
+{
+        struct fb_event event;
+        struct fb_blit_caps caps, fbcaps;
+        int err = 0;
+
+        memset(&caps, 0, sizeof(caps));
+        memset(&fbcaps, 0, sizeof(fbcaps));
+        caps.flags = (activate & FB_ACTIVATE_ALL) ? 1 : 0;
+        event.info = info;
+        event.data = &caps;
+        fb_notifier_call_chain(FB_EVENT_GET_REQ, &event);
+        info->fbops->fb_get_caps(info, &fbcaps, var);
+
+        if (((fbcaps.x ^ caps.x) & caps.x) ||
+            ((fbcaps.y ^ caps.y) & caps.y) ||
+            (fbcaps.len < caps.len))
+                err = -EINVAL;
+
+        return err;
+}
+
 int
 fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
 {
@@ -817,7 +840,15 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
                         struct fb_videomode mode;
                         int err = 0;
 
+                        if (info->fbops->fb_get_caps) {
+                                err = fb_check_caps(info, var, activate);
+
+                                if (err)
+                                        goto done;
+                        }
+
                         info->var = *var;
+
                         if (info->fbops->fb_set_par)
                                 info->fbops->fb_set_par(info);
 
@@ -843,6 +874,8 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
                         }
                 }
         }
+
+ done:
         return 0;
 }
 
diff --git a/include/linux/fb.h b/include/linux/fb.h
index a2f382c01cd2..dff7a728948c 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -527,12 +527,20 @@ struct fb_cursor_user {
 #define FB_EVENT_MODE_CHANGE_ALL        0x0B
 /*      A software display blank change occured */
 #define FB_EVENT_CONBLANK               0x0C
+/*      Get drawing requirements        */
+#define FB_EVENT_GET_REQ                0x0D
 
 struct fb_event {
         struct fb_info *info;
         void *data;
 };
 
+struct fb_blit_caps {
+        u32 x;
+        u32 y;
+        u32 len;
+        u32 flags;
+};
 
 extern int fb_register_client(struct notifier_block *nb);
 extern int fb_unregister_client(struct notifier_block *nb);
@@ -652,6 +660,10 @@ struct fb_ops {
 
         /* restore saved state */
         void (*fb_restore_state)(struct fb_info *info);
+
+        /* get capability given var */
+        void (*fb_get_caps)(struct fb_info *info, struct fb_blit_caps *caps,
+                            struct fb_var_screeninfo *var);
 };
 
 #ifdef CONFIG_FB_TILEBLITTING