Kernel: Add horizontal mouse scroll support

Author: https://github.com/can3p
Commit: https://github.com/SerenityOS/serenity/commit/d61cc47055e
Pull-request: https://github.com/SerenityOS/serenity/pull/11246
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Kernel/API/MousePacket.h

@@ -12,6 +12,7 @@ struct MousePacket {
     int x { 0 };
     int y { 0 };
     int z { 0 };
+    int w { 0 };
 
     enum Button {
         LeftButton = 0x01,

Kernel/Devices/HID/MouseDevice.cpp

@@ -35,7 +35,7 @@ ErrorOr<size_t> MouseDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer&
         lock.unlock();
 
         dbgln_if(MOUSE_DEBUG, "Mouse Read: Buttons {:x}", packet.buttons);
-        dbgln_if(MOUSE_DEBUG, "PS2 Mouse: X {}, Y {}, Z {}, Relative {}", packet.x, packet.y, packet.z, packet.buttons);
+        dbgln_if(MOUSE_DEBUG, "PS2 Mouse: X {}, Y {}, Z {}, W {}, Relative {}", packet.x, packet.y, packet.z, packet.w, packet.buttons);
         dbgln_if(MOUSE_DEBUG, "PS2 Mouse Read: Filter packets");
 
         size_t bytes_read_from_packet = min(remaining_space_in_buffer, sizeof(MousePacket));

Kernel/Devices/HID/PS2MouseDevice.cpp

@@ -89,6 +89,7 @@ MousePacket PS2MouseDevice::parse_data_packet(const RawPacket& raw_packet)
     int x = raw_packet.bytes[1];
     int y = raw_packet.bytes[2];
     int z = 0;
+    int w = 0;
     if (m_has_wheel) {
         // FIXME: For non-Intellimouse, this is a full byte.
         //        However, for now, m_has_wheel is only set for Intellimouse.
@@ -97,6 +98,14 @@ MousePacket PS2MouseDevice::parse_data_packet(const RawPacket& raw_packet)
         // -1 in 4 bits
         if (z == 15)
             z = -1;
+
+        if ((raw_packet.bytes[3] & 0xc0) == 0x40) {
+            // FIXME: Scroll only functions correctly when the sign is flipped there
+            w = -z;
+            z = 0;
+        } else {
+            w = 0;
+        }
     }
     bool x_overflow = raw_packet.bytes[0] & 0x40;
     bool y_overflow = raw_packet.bytes[0] & 0x80;
@@ -114,6 +123,7 @@ MousePacket PS2MouseDevice::parse_data_packet(const RawPacket& raw_packet)
     packet.x = x;
     packet.y = y;
     packet.z = z;
+    packet.w = w;
     packet.buttons = raw_packet.bytes[0] & 0x07;
 
     if (m_has_five_buttons) {
@@ -125,7 +135,7 @@ MousePacket PS2MouseDevice::parse_data_packet(const RawPacket& raw_packet)
 
     packet.is_relative = true;
     dbgln_if(PS2MOUSE_DEBUG, "PS2 Relative Mouse: Buttons {:x}", packet.buttons);
-    dbgln_if(PS2MOUSE_DEBUG, "Mouse: X {}, Y {}, Z {}", packet.x, packet.y, packet.z);
+    dbgln_if(PS2MOUSE_DEBUG, "Mouse: X {}, Y {}, Z {}, W {}", packet.x, packet.y, packet.z, packet.w);
     return packet;
 }
 

Kernel/Devices/VMWareBackdoor.cpp

@@ -211,16 +211,28 @@ MousePacket VMWareBackdoor::receive_mouse_packet()
     int x = command.bx;
     int y = command.cx;
     int z = static_cast<i8>(command.dx); // signed 8 bit value only!
+    int w = 0;
+
+    // horizontal scroll is reported as +-2 by qemu
+    // FIXME: Scroll only functions correctly when the sign is flipped there
+    if (z == 2) {
+        w = -1;
+        z = 0;
+    } else if (z == -2) {
+        w = 1;
+        z = 0;
+    }
 
     if constexpr (PS2MOUSE_DEBUG) {
         dbgln("Absolute Mouse: Buttons {:x}", buttons);
-        dbgln("Mouse: x={}, y={}, z={}", x, y, z);
+        dbgln("Mouse: x={}, y={}, z={}, w={}", x, y, z, w);
     }
 
     MousePacket packet;
     packet.x = x;
     packet.y = y;
     packet.z = z;
+    packet.w = w;
     if (buttons & VMMOUSE_LEFT_CLICK)
         packet.buttons |= MousePacket::LeftButton;
     if (buttons & VMMOUSE_RIGHT_CLICK)

Userland/Services/WindowServer/EventLoop.cpp

@@ -64,7 +64,7 @@ void EventLoop::drain_mouse()
     bool state_is_sent = false;
     for (size_t i = 0; i < npackets; ++i) {
         auto& packet = packets[i];
-        dbgln_if(WSMESSAGELOOP_DEBUG, "EventLoop: Mouse X {}, Y {}, Z {}, relative={}", packet.x, packet.y, packet.z, packet.is_relative);
+        dbgln_if(WSMESSAGELOOP_DEBUG, "EventLoop: Mouse X {}, Y {}, Z {}, W {}, relative={}", packet.x, packet.y, packet.z, packet.w, packet.is_relative);
 
         state.is_relative = packet.is_relative;
         if (packet.is_relative) {
@@ -75,6 +75,7 @@ void EventLoop::drain_mouse()
             state.y = packet.y;
         }
         state.z += packet.z;
+        state.w += packet.w;
         state_is_sent = false;
 
         if (packet.buttons != state.buttons) {
@@ -100,12 +101,13 @@ void EventLoop::drain_mouse()
                 state.x = 0;
                 state.y = 0;
                 state.z = 0;
+                state.w = 0;
             }
         }
     }
     if (state_is_sent)
         return;
-    if (state.is_relative && (state.x || state.y || state.z))
+    if (state.is_relative && (state.x || state.y || state.z || state.w))
         screen_input.on_receive_mouse_data(state);
     if (!state.is_relative)
         screen_input.on_receive_mouse_data(state);