From aa5ef742f68127c6222ed8f087d76fdadd1dde05 Mon Sep 17 00:00:00 2001
From: Maxim Poliakovski <maximumspatium@googlemail.com>
Date: Mon, 9 Oct 2023 19:18:55 +0200
Subject: [PATCH] atirage: return meaningful value for GUI_STAT:GUI_FIFO.

---
 devices/video/atirage.cpp | 5 +++++
 devices/video/atirage.h   | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/devices/video/atirage.cpp b/devices/video/atirage.cpp
index 462176f..4ab00d2 100644
--- a/devices/video/atirage.cpp
+++ b/devices/video/atirage.cpp
@@ -106,9 +106,11 @@ ATIRage::ATIRage(uint16_t dev_id)
     switch (dev_id) {
     case ATI_RAGE_GT_DEV_ID:
         asic_id = 0x9A; // GT-B2U3 fabricated by UMC
+        this->cmd_fifo_size = 48;
         break;
     case ATI_RAGE_PRO_DEV_ID:
         asic_id = 0x5C; // R3B/D/P-A4 fabricated by UMC
+        this->cmd_fifo_size = 128;
         break;
     default:
         asic_id = 0xDD;
@@ -244,6 +246,9 @@ uint32_t ATIRage::read_reg(uint32_t reg_offset, uint32_t size) {
             }
         }
         break;
+    case ATI_GUI_STAT:
+        result = this->cmd_fifo_size << 16; // HACK: tell the guest the command FIFO is empty
+        break;
     default:
         result = this->regs[reg_offset >> 2];
     }
diff --git a/devices/video/atirage.h b/devices/video/atirage.h
index 7c36abe..578c3b2 100644
--- a/devices/video/atirage.h
+++ b/devices/video/atirage.h
@@ -84,6 +84,8 @@ private:
     uint32_t    regs[512] = {}; // internal registers
     uint8_t     plls[64]  = {}; // internal PLL registers
 
+    uint8_t     cmd_fifo_size = 0;
+
     // Video RAM variables
     std::unique_ptr<uint8_t[]>  vram_ptr;
     uint32_t    vram_size;