refactor the hardware boot screen

- remove a blanking operation. this makes the transision from
loader to runtime almost imperceptably smoother
- add the ability to summon the logo screen earlier in the process

Note that only GAM can call GFX, so, it's alright to expose that
API, since GAM should gate-keep and prevent abuse of that function.

services/graphics-server/src/api.rs

@@ -119,6 +119,9 @@ pub(crate) enum Opcode {
     /// SuspendResume callback
     SuspendResume,
 
+    /// draw the boot logo (for continuity as apps initialize)
+    DrawBootLogo,
+
     Quit,
 }
 

services/graphics-server/src/backend/betrusted.rs

@@ -68,7 +68,6 @@ impl XousDisplay {
         display
             .susres
             .push(RegOrField::Field(utra::memlcd::PRESCALER_PRESCALER), None);
-        display.sync_clear();
 
         /*
         use log::{error, info};
@@ -255,6 +254,7 @@ impl XousDisplay {
 
     /// "synchronous clear" -- must be called on init, so that the state of the LCD
     /// internal memory is consistent with the state of the frame buffer
+    /*
     fn sync_clear(&mut self) {
         let framebuffer = self.fb.as_mut_ptr() as *mut u32;
         for words in 0..FB_SIZE {
@@ -267,6 +267,7 @@ impl XousDisplay {
         self.update_all(); // because we force an all update here
         while self.busy() {}
     }
+    */
 
     fn busy(&self) -> bool {
         self.csr.rf(utra::memlcd::BUSY_BUSY) == 1

services/graphics-server/src/lib.rs

@@ -108,6 +108,14 @@ impl Gfx {
         .map(|_| ())
     }
 
+    pub fn draw_boot_logo(&self) -> Result<(), xous::Error> {
+        send_message(
+            self.conn,
+            Message::new_scalar(Opcode::DrawBootLogo.to_usize().unwrap(), 0, 0, 0, 0),
+        )
+        .map(|_| ())
+    }
+
     pub fn screen_size(&self) -> Result<Point, xous::Error> {
         let response = send_message(
             self.conn,

services/graphics-server/src/main.rs

@@ -112,6 +112,7 @@ fn wrapped_main() -> ! {
     log::info!("my PID is {}", xous::process::id());
 
     let mut display = XousDisplay::new();
+    draw_boot_logo(&mut display); // bring this up as soon as possible
     let fontregion = map_fonts();
 
     // install the graphical panic handler. It won't catch really early panics, or panics in this crate,
@@ -139,8 +140,6 @@ fn wrapped_main() -> ! {
         .register_name(api::SERVER_NAME_GFX, Some(1))
         .expect("can't register server");
 
-    draw_boot_logo(&mut display);
-
     let screen_clip = Rectangle::new(Point::new(0, 0), display.screen_size());
 
     display.redraw();
@@ -459,6 +458,11 @@ fn wrapped_main() -> ! {
                     display.update();
                     display.redraw();
                 }),
+                Some(Opcode::DrawBootLogo) => msg_scalar_unpack!(msg, _, _, _, _, {
+                    display.blit_screen(&poweron::LOGO_MAP);
+                    display.update();
+                    display.redraw();
+                }),
                 Some(Opcode::Devboot) => msg_scalar_unpack!(msg, ena, _, _, _, {
                     if ena != 0 {
                         display.set_devboot(true);