fbdev: fbcon: check if mode can handle new screen
Antonino A. Daplas [Tue, 8 May 2007 07:39:37 +0000 (00:39 -0700)]
Check if the mode can properly display the screen.  This will be needed by
drivers where the capability is not constant with each mode.  The function
fb_set_var() will query fbcon the requirement, then it will query the driver
(via a new hook fb_get_caps()) its capability.  If the driver's capability
cannot handle fbcon's requirement, then fb_set_var() will fail.

For example, if a particular driver supports 2 modes where:

mode1 = can only display 8x16 bitmaps
mode2 = can display any bitmap

then if current mode = mode2 and current font = 12x22

fbset <mode1> /* mode1 cannot handle 12x22 */
fbset will fail

Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/console/fbcon.c
drivers/video/fbmem.c
include/linux/fb.h

index 6fc3501..34899bd 100644 (file)
@@ -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:
index cd14079..354711c 100644 (file)
@@ -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;
 }
 
index a2f382c..dff7a72 100644 (file)
@@ -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