feat: unify system status codes

kernel/src/Api/Graphics.hpp

@@ -118,18 +118,18 @@ namespace montauk::abi {
         if ((int64_t)index == -1) {
             return GPU::FlipSupported() ? 1 : 0;
         }
-        if (!GPU::FlipSupported()) return -1;
+        if (!GPU::FlipSupported()) return UnsupportedOp;
 
         auto* proc = Sched::GetCurrentProcessPtr();
         if ((int64_t)index == -2) {
-            return proc != nullptr ? GPU::AcquireFlip(proc->pid) : -1;
+            return proc != nullptr ? GPU::AcquireFlip(proc->pid) : GenericFailure;
         }
-        if (proc == nullptr) return -1;
+        if (proc == nullptr) return GenericFailure;
         return GPU::Flip((int)index, (flags & 1) != 0, proc->pid);
     }
 
     static int64_t Sys_DisplayInfo(DisplayInfo* out) {
-        return Drivers::Graphics::IntelGPU::GetDisplayInfo(out) ? 0 : -1;
+        return Drivers::Graphics::IntelGPU::GetDisplayInfo(out) ? Success : NoDevice;
     }
 
     static int64_t Sys_DisplayModes(DisplayModeInfo* out, int maxCount) {
@@ -137,7 +137,12 @@ namespace montauk::abi {
     }
 
     static int64_t Sys_DisplaySetMode(int modeIndex) {
-        return Drivers::Graphics::IntelGPU::SetDisplayMode(modeIndex);
+        // The driver answers -2 for a mode that would need link retraining
+        // and -3 for a modeset that failed and was rolled back.
+        int64_t rc = Drivers::Graphics::IntelGPU::SetDisplayMode(modeIndex);
+        if (rc == -2) return UnsupportedOp;
+        if (rc == -3) return IoFailure;
+        return rc;
     }
 
     static int64_t Sys_DisplayBrightness(int percent) {