Merge branch 'late_disable_graphic_debug' into 'master'

graphics/vesad: Disable kernel graphical debug as late as possible

See merge request redox-os/drivers!262

graphics/vesad/src/main.rs

@@ -3,9 +3,10 @@ extern crate syscall;
 
 use driver_graphics::GraphicsScheme;
 use event::{user_data, EventQueue};
-use inputd::DisplayHandle;
+use inputd::{DisplayHandle, VtEventKind};
 use std::env;
 use std::fs::File;
+use std::io::Write;
 use std::os::fd::AsRawFd;
 
 use crate::framebuffer::FrameBuffer;
@@ -104,7 +105,10 @@ fn inner(daemon: redox_daemon::Daemon, framebuffers: Vec<FrameBuffer>) -> ! {
         )
         .unwrap();
 
-    let _ = File::open("/scheme/debug/disable-graphical-debug");
+    let mut disable_graphical_debug = Some(
+        File::open("/scheme/debug/disable-graphical-debug")
+            .expect("vesad: Failed to open /scheme/debug/disable-graphical-debug"),
+    );
 
     libredox::call::setrens(0, 0).expect("vesad: failed to enter null namespace");
 
@@ -121,6 +125,16 @@ fn inner(daemon: redox_daemon::Daemon, framebuffers: Vec<FrameBuffer>) -> ! {
                     .read_vt_event()
                     .expect("vesad: failed to read display handle")
                 {
+                    if let VtEventKind::Activate = vt_event.kind {
+                        // Disable the kernel graphical debug writing once switching vt's for the
+                        // first time. This way the kernel graphical debug remains enabled if the
+                        // userspace logging infrastructure doesn't start up because for example a
+                        // kernel panic happened prior to it starting up or logd crashed.
+                        if let Some(mut disable_graphical_debug) = disable_graphical_debug.take() {
+                            let _ = disable_graphical_debug.write(&[1]);
+                        }
+                    }
+
                     scheme.handle_vt_event(vt_event);
                 }
             }