GPU: Fire GPU interrupts at the correct places.

PDC0 and PDC1 are both VBlank interrupts. PDC0 was being treated as a
HBlank interrupt and fired many more times than it should. They now both
fire together at 60 Hz. This puzzlingly *improves* apparent framerate on
many applications.

A few other interrupts were being fired inside the GSP command
processing instead of on the actual GPU register writes, so they were
moved there, which should cover direct writes tho those registers not
going through the GX command queue.

src/core/hle/service/gsp_gpu.cpp

@@ -269,8 +269,6 @@ static void ExecuteCommand(const Command& command, u32 thread_id) {
         WriteGPURegister(GPU_REG_INDEX(memory_fill_config[1].address_end), Memory::VirtualToPhysicalAddress(params.end2) >> 3);
         WriteGPURegister(GPU_REG_INDEX(memory_fill_config[1].size), params.end2 - params.start2);
         WriteGPURegister(GPU_REG_INDEX(memory_fill_config[1].value), params.value2);
-
-        SignalInterrupt(InterruptId::PSC0);
         break;
     }
 
@@ -284,10 +282,6 @@ static void ExecuteCommand(const Command& command, u32 thread_id) {
         WriteGPURegister(GPU_REG_INDEX(display_transfer_config.flags), params.flags);
         WriteGPURegister(GPU_REG_INDEX(display_transfer_config.trigger), 1);
 
-        // TODO(bunnei): Determine if these interrupts should be signalled here.
-        SignalInterrupt(InterruptId::PSC1);
-        SignalInterrupt(InterruptId::PPF);
-
         // Update framebuffer information if requested
         for (int screen_id = 0; screen_id < 2; ++screen_id) {
             FrameBufferUpdate* info = GetFrameBufferInfo(thread_id, screen_id);

src/core/hw/gpu.cpp

@@ -27,8 +27,6 @@ Regs g_regs;
 bool g_skip_frame = false;              ///< True if the current frame was skipped
 
 static u64 frame_ticks      = 0;        ///< 268MHz / gpu_refresh_rate frames per second
-static u64 line_ticks       = 0;        ///< Number of ticks for a screen line
-static u32 cur_line         = 0;        ///< Current screen line
 static u64 last_update_tick = 0;        ///< CPU ticl count from last GPU update
 static u64 frame_count      = 0;        ///< Number of frames drawn
 static bool last_skip_frame = false;    ///< True if the last frame was skipped
@@ -79,6 +77,12 @@ inline void Write(u32 addr, const T data) {
                 *ptr = bswap32(config.value); // TODO: This is just a workaround to missing framebuffer format emulation
 
             LOG_TRACE(HW_GPU, "MemoryFill from 0x%08x to 0x%08x", config.GetStartAddress(), config.GetEndAddress());
+
+            if (!is_second_filler) {
+                GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PSC0);
+            } else {
+                GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PSC1);
+            }
         }
         break;
     }
@@ -152,6 +156,8 @@ inline void Write(u32 addr, const T data) {
                       config.GetPhysicalInputAddress(), (u32)config.input_width, (u32)config.input_height,
                       config.GetPhysicalOutputAddress(), (u32)config.output_width, (u32)config.output_height,
                       config.output_format.Value());
+
+            GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PPF);
         }
         break;
     }
@@ -193,20 +199,14 @@ void Update() {
     // blank, we need to simulate it. Based on testing, it seems that retail applications work more
     // accurately when this is signalled between thread switches.
 
-    if (HLE::g_reschedule) {
-        u64 current_ticks = Core::g_app_core->GetTicks();
-        u32 num_lines = static_cast<u32>((current_ticks - last_update_tick) / line_ticks);
+    u64 current_ticks = Core::g_app_core->GetTicks();
 
-        // Synchronize line...
-        if (num_lines > 0) {
-            GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PDC0);
-            cur_line += num_lines;
-            last_update_tick += (num_lines * line_ticks);
-        }
+
+    if (HLE::g_reschedule) {
 
         // Synchronize frame...
-        if (cur_line >= framebuffer_top.height) {
-            cur_line = 0;
+        if ((current_ticks - last_update_tick) >= frame_ticks) {
+            last_update_tick += frame_ticks;
             frame_count++;
             last_skip_frame = g_skip_frame;
             g_skip_frame = (frame_count & Settings::values.frame_skip) != 0;
@@ -223,6 +223,11 @@ void Update() {
             }
 
             // Signal to GSP that GPU interrupt has occurred
+            // TODO(yuriks): hwtest to determine if PDC0 is for the Top screen and PDC1 for the Sub
+            // screen, or if both use the same interrupts and these two instead determine the
+            // beginning and end of the VBlank period. If needed, split the interrupt firing into
+            // two different intervals.
+            GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PDC0);
             GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PDC1);
 
             // TODO(bunnei): Fake a DSP interrupt on each frame. This does not belong here, but
@@ -264,8 +269,6 @@ void Init() {
     framebuffer_sub.active_fb = 0;
 
     frame_ticks = 268123480 / Settings::values.gpu_refresh_rate;
-    line_ticks = (GPU::frame_ticks / framebuffer_top.height);
-    cur_line = 0;
     last_update_tick = Core::g_app_core->GetTicks();
     last_skip_frame = false;
     g_skip_frame = false;