From a4316e2aa71c282d646c84b1dc4fa9df80d4854e Mon Sep 17 00:00:00 2001
From: bunnie <bunnie@kosagi.com>
Date: Sun, 24 May 2026 00:45:13 +0800
Subject: [PATCH] add dry-run api to gfx

dry-runs are useful for warming up "hot paths" in UI code
to improve latency. This is specifically a feature for tuning
interactions on systems that have swap memory.
---
 libs/ux-api/src/service/api.rs |  4 ++++
 libs/ux-api/src/service/gfx.rs | 15 +++++++++++++++
 services/bao-video/src/main.rs | 23 +++++++++++++++++------
 3 files changed, 36 insertions(+), 6 deletions(-)

diff --git a/libs/ux-api/src/service/api.rs b/libs/ux-api/src/service/api.rs
index 344dfc561..8da3d1ecc 100644
--- a/libs/ux-api/src/service/api.rs
+++ b/libs/ux-api/src/service/api.rs
@@ -117,6 +117,10 @@ pub enum GfxOpcode {
     Brightness,
     #[cfg(feature = "board-baosec")]
     FlipScreen,
+    /// This is used to toggle DryRun mode. The purpose of this mode is to
+    /// warm up UI routines from swap memory to improve UI latency.
+    #[cfg(feature = "board-baosec")]
+    DryRun,
 
     /// Gutter for invalid calls
     InvalidCall,
diff --git a/libs/ux-api/src/service/gfx.rs b/libs/ux-api/src/service/gfx.rs
index 1c88a073e..3222b68d4 100644
--- a/libs/ux-api/src/service/gfx.rs
+++ b/libs/ux-api/src/service/gfx.rs
@@ -848,6 +848,21 @@ impl Gfx {
         .map(|_| ())
     }
 
+    #[cfg(feature = "board-baosec")]
+    pub fn dry_run(&self, dry_run: bool) -> Result<(), xous::Error> {
+        send_message(
+            self.conn,
+            Message::new_blocking_scalar(
+                GfxOpcode::DryRun.to_usize().unwrap(),
+                if dry_run { 1 } else { 0 },
+                0,
+                0,
+                0,
+            ),
+        )
+        .map(|_| ())
+    }
+
     #[cfg(feature = "hosted-baosec")]
     pub fn acquire_qr(&self) -> Result<QrAcquisition, xous::Error> {
         let dummy = "otpauth://totp/ACME%20Co:john.doe@email.com?secret=HXDMVJECJJWSRB3HWIZR4IFUGFTMXBOZ&issuer=ACME%20Co&algorithm=SHA1&digits=6&period=30".to_string();
diff --git a/services/bao-video/src/main.rs b/services/bao-video/src/main.rs
index ea6f9f744..b291de921 100644
--- a/services/bao-video/src/main.rs
+++ b/services/bao-video/src/main.rs
@@ -433,6 +433,7 @@ pub fn wrapped_main(main_thread_token: MainThreadToken) -> ! {
     let mut qr_request: Option<xous::MessageEnvelope> = None;
     let mut kbd_listeners: Vec<(CID, usize)> = Vec::new();
     let cam_started = Arc::new(AtomicBool::new(false));
+    let mut dry_run = false;
     #[allow(unused_mut)]
     let mut orientation = DisplayOrientation::Normal;
     loop {
@@ -851,9 +852,11 @@ pub fn wrapped_main(main_thread_token: MainThreadToken) -> ! {
                 GfxOpcode::Flush => {
                     if qr_request.is_none() {
                         log::trace!("***gfx flush*** redraw##");
-                        display
-                            .redraw()
-                            .unwrap_or_else(|_| display_timeout_handler(&udma_global, &mut display));
+                        if !dry_run {
+                            display
+                                .redraw()
+                                .unwrap_or_else(|_| display_timeout_handler(&udma_global, &mut display));
+                        }
                     }
                 }
                 GfxOpcode::Clear => {
@@ -1001,12 +1004,20 @@ pub fn wrapped_main(main_thread_token: MainThreadToken) -> ! {
                             display
                                 .flip_vertical(scalar.arg1 != 0)
                                 .unwrap_or_else(|_| display_timeout_handler(&udma_global, &mut display));
-                            display
-                                .redraw()
-                                .unwrap_or_else(|_| display_timeout_handler(&udma_global, &mut display));
+                            if !dry_run {
+                                display
+                                    .redraw()
+                                    .unwrap_or_else(|_| display_timeout_handler(&udma_global, &mut display));
+                            }
                         }
                     }
                 }
+                #[cfg(feature = "board-baosec")]
+                GfxOpcode::DryRun => {
+                    if let Some(scalar) = msg.body.scalar_message_mut() {
+                        dry_run = scalar.arg1 != 0;
+                    }
+                }
                 GfxOpcode::Quit => {
                     log::info!("refusing to quit, this operation is not supported on this platform!");
                 }