From b58ca7cf3d73152e8e049df4ddd43912030ab4ea Mon Sep 17 00:00:00 2001 From: Luke Date: Tue, 25 Aug 2020 05:51:15 +0100 Subject: [PATCH] Kernel: Scroll wheel amount on Intellimouse is 4 bits instead of 8 When trying to scroll up on virtualizers that don't use the VMware backdoor and instead use PS2MouseDevice, it would actually scroll down rapidly. Looking into it, the mouse delta for scrolling down was 1 and 15 for scrolling up. 15 is suspiciously -1 for a nibble. According to https://isdaman.com/alsos/hardware/mouse/ps2interface.htm the Z is actually 4 bits for Intellimouse. This fixes scrolling up on virtualizers such as VirtualBox. --- Kernel/Devices/PS2MouseDevice.cpp | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/Kernel/Devices/PS2MouseDevice.cpp b/Kernel/Devices/PS2MouseDevice.cpp index e4461abaad..47f876515b 100644 --- a/Kernel/Devices/PS2MouseDevice.cpp +++ b/Kernel/Devices/PS2MouseDevice.cpp @@ -136,8 +136,15 @@ void PS2MouseDevice::parse_data_packet() int x = m_data[1]; int y = m_data[2]; int z = 0; - if (m_has_wheel) - z = (char)m_data[3]; + if (m_has_wheel) { + // FIXME: For non-Intellimouse, this is a full byte. + // However, for now, m_has_wheel is only set for Intellimouse. + z = (char)(m_data[3] & 0x0f); + + // -1 in 4 bits + if (z == 15) + z = -1; + } bool x_overflow = m_data[0] & 0x40; bool y_overflow = m_data[0] & 0x80; bool x_sign = m_data[0] & 0x10;