fix wheel on t5710

3 files changed, 51 insertions, 12 deletions

diff --git a/README.md b/README.md
index f647386..af3eb1d 100644
--- a/README.md
+++ b/README.md
@@ -85,8 +85,10 @@ the following additional features:
   Note *wheel support is broken when running under 386-enhanced mode Windows*, 
   since it will not let PS/2 wheel data reach the DOS driver.
 
-* Sending fake keys on wheel movements, i.e. faking wheel scroll support using arrow up/down keys.
-  You can scroll with the mouse wheel inside MS-DOS Edit!  
+* **Sending scroll keys on wheel movements**,
+  i.e. faking wheel scroll support on programs that don't support the CuteMouse API
+  by using arrow up/down keys.
+  You can now scroll with the mouse wheel inside MS-DOS Edit!  
   This is not enabled by default, see `wheelkey` below.
 
 * The current version uses about 10KiB of memory (when logging is disabled),
@@ -96,7 +98,7 @@ the following additional features:
 * A companion driver for Windows 3.x (_VBMOUSE.DRV_) that uses this driver 
   (via int33h) instead of accessing the mouse directly,
   so that Windows 3.x gains some of the features of this driver
-  (like mouse integration in VirtualBox).  
+  (like mouse integration in VirtualBox/VMware).  
   There is some preliminary mouse wheel support based on the ideas from
   [vmwmouse](https://github.com/NattyNarwhal/vmwmouse/issues/5),
   but it only works under real-mode Windows. 
@@ -433,6 +435,15 @@ to obtain mouse button presses (and wheel movement) is still through the PS/2 co
 * Get the scroll wheel to work under 386-enhanced Windows, but this requires
   looking into VKD.386 (or a replacement of it).
 
+* Investigate whether it makes sense to configure the PS/2 BIOS in "1 packet mode"
+  like the [Microsoft Mouse driver does](https://www.betaarchive.com/wiki/index.php/Microsoft_KB_Archive/97883)
+  to aid scroll wheel compatibility. Currently we set it to either 3 packet
+  or 4 packet depending on whether we detect a wheel mouse or not.
+
+* The VirtualBox BIOS can crash on warm-boot (e.g. Ctrl+Alt+Del) if the mouse
+  was in the middle of sending a packet. A VM reboot fixes it.
+  We probably need to hook Ctrl+Alt+Del and turn off the mouse.
+
 * VMware shared folders support is interesting, but there is very little 
   documentation that I can find, no sample code, and no open source implementation.  
   Also, unlike VBMOUSE, where most of the code  is common to all virtualizers,
diff --git a/mousetsr.c b/mousetsr.c
index 4fcc381..c0077ec 100644
--- a/mousetsr.c
+++ b/mousetsr.c
@@ -679,7 +679,7 @@ static void handle_mouse_event(uint16_t buttons, bool absolute, int x, int y, in
 				for (; z < 0; z++) {
 					int16_store_keystroke(data.wheel_up_key);
 				}
-			} else if (z > 0 && data.wheel_up_key) {
+			} else if (z > 0 && data.wheel_down_key) {
 				for (; z > 0; z--) {
 					int16_store_keystroke(data.wheel_down_key);
 				}
@@ -751,6 +751,8 @@ static void ps2_mouse_handler(uint16_t word1, uint16_t word2, uint16_t word3, ui
 #endif /* TRACE_EVENTS */
 
 	// Decode the PS2 event args
+
+#if USE_WHEEL
 	// In a normal IBM PS/2 BIOS (incl. VirtualBox/Bochs/qemu/SeaBIOS):
 	//  word1 low byte = status (following PS2M_STATUS_*)
 	//  word2 low byte = x
@@ -763,18 +765,40 @@ static void ps2_mouse_handler(uint16_t word1, uint16_t word2, uint16_t word3, ui
 	//  word2 low byte = y
 	//  word3 low byte = z
 	//  word4 = always zero
-	// VirtualBox/Bochs/qemu/SeaBIOS behave like a normal one,
-	// but they also store the raw contents of all mouse packets in the EBDA (starting 0x28 = packet 0).
+	// Real hardware seems to be of either type.
+	// VirtualBox/Bochs/qemu/SeaBIOS also store the raw contents of all mouse
+	// packets in the EBDA reserved area (starting 0x28 = packet 0).
 	// Other BIOSes don't do that so it is not a reliable option either.
 	// So, how to detect which BIOS we have?
-	// For now we are always assuming "normal" PS/2 BIOS.
-	// But with VirtualBox integration on we'll get the wheel packet from the EBDA,
-	// and with VMWare integration on we'll get it from the VMware protocol.
+
+	// First, we'll only read the EBDA if we have confirmed VirtualBox (see USE_VIRTUALBOX below)
+	//  For VirtualBox VMs this is mandatory since we have no other way of getting wheel data
+	//  For qemu VMs, we can still get to wheel data via the vmmouse interface (and we'll do that).
+	// Second, the moment we see that the high byte of word1 is not 0,
+	// we'll assume the BIOS is of the second type, and remember that.
+	// (since when there is no movement, x would be 0 anyway!)
+
+	if (word1 & 0xFF00) data.bios_x_on_status = true;
+
+	if (data.haswheel && data.bios_x_on_status) {
+		status = (uint8_t) word1;
+		x = (uint8_t) (word1 >> 8);
+		y = (uint8_t) word2;
+		z = (int8_t) word3; // Sign-extend z packet
+	} else {
+		status = (uint8_t) word1;
+		x = (uint8_t) word2;
+		y = (uint8_t) word3;
+		z = 0;
+	}
+#else
 	status = (uint8_t) word1;
 	x = (uint8_t) word2;
 	y = (uint8_t) word3;
 	z = 0;
-	(void) word4;
+#endif
+
+	(void) word4; // This appears to be never used on either type of BIOS
 
 	// Sign-extend X, Y as per the status byte
 	x =   status & PS2M_STATUS_X_NEG ? 0xFF00 | x : x;
@@ -946,6 +970,7 @@ static void reset_mouse_hardware()
 	ps2m_enable(false);
 
 #if USE_WHEEL
+	data.bios_x_on_status = false;
 	if (data.usewheel && ps2m_detect_wheel()) {
 		dlog_puts("PS/2 wheel detected");
 		data.haswheel = true;
diff --git a/mousetsr.h b/mousetsr.h
index 0bb234f..00646db 100644
--- a/mousetsr.h
+++ b/mousetsr.h
@@ -37,7 +37,7 @@
 /** Enable the wheel. */
 #define USE_WHEEL 1
 /** Trace events verbosily */
-#define TRACE_EVENTS 1
+#define TRACE_EVENTS 0
 
 #define VERSION_MAJOR 0
 #define VERSION_MINOR 5
@@ -102,7 +102,10 @@ typedef struct tsrdata {
 	// Detected mouse hardware
 #if USE_WHEEL
 	/** Whether the current mouse has a wheel (and support is enabled). */
-	bool haswheel;
+	bool haswheel : 1;
+	/** Whether the current PS/2 BIOS seems to be putting the first packet
+	 *  on the high byte of the first word when we use wheel mouse. */
+	bool bios_x_on_status : 1;
 #endif
 
 	// Current mouse settings