OvmfPkg: QemuVideoDxe: filter BOCHS modes vs. available frame buffer size

In the next patch we'll add many new BOCHS modes, some of which require
large frame buffers.

The size of the QXL VGA compatibility framebuffer can be changed with the

  -global qxl-vga.vgamem_mb=$NUM_MB

QEMU option.

If $NUM_MB would exceed 32, then the following two QEMU options are
necessary instead:

  -global qxl-vga.vgamem_mb=$NUM_MB         \
  -global qxl-vga.ram_size_mb=$((NUM_MB*2))

because the compatibility framebuffer can't cover more than half of PCI
BAR #0. The latter defaults to 64MB in size, and is controlled by
"ram_size_mb".

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15288 6f19259b-4bc3-4df7-8a09-765794883524

diff --git a/OvmfPkg/QemuVideoDxe/Initialize.c b/OvmfPkg/QemuVideoDxe/Initialize.c
index af3b6af47cecb77c73d3b0b963436c4345cd4fc3..80e9b3a936ff571d03ed0d51af7be054695819e8 100644 (file)
--- a/OvmfPkg/QemuVideoDxe/Initialize.c
+++ b/OvmfPkg/QemuVideoDxe/Initialize.c
@@ -200,7 +200,7 @@ QemuVideoCirrusModeSetup (
     ModeData ++ ;\r
     VideoMode ++;\r
   }\r
-  Private->MaxMode = QEMU_VIDEO_CIRRUS_MODE_COUNT;\r
+  Private->MaxMode = ModeData - Private->ModeData;\r
 \r
   return EFI_SUCCESS;\r
 }\r
@@ -222,10 +222,19 @@ QemuVideoBochsModeSetup (
   QEMU_VIDEO_PRIVATE_DATA  *Private\r
   )\r
 {\r
+  UINT32                                 AvailableFbSize;\r
   UINT32                                 Index;\r
   QEMU_VIDEO_MODE_DATA                   *ModeData;\r
   QEMU_VIDEO_BOCHS_MODES                 *VideoMode;\r
 \r
+  //\r
+  // fetch available framebuffer size\r
+  //\r
+  AvailableFbSize  = BochsRead (Private, VBE_DISPI_INDEX_VIDEO_MEMORY_64K);\r
+  AvailableFbSize *= SIZE_64KB;\r
+  DEBUG ((EFI_D_VERBOSE, "%a: AvailableFbSize=0x%x\n", __FUNCTION__,\r
+    AvailableFbSize));\r
+\r
   //\r
   // Setup Video Modes\r
   //\r
@@ -238,25 +247,32 @@ QemuVideoBochsModeSetup (
   ModeData = Private->ModeData;\r
   VideoMode = &QemuVideoBochsModes[0];\r
   for (Index = 0; Index < QEMU_VIDEO_BOCHS_MODE_COUNT; Index ++) {\r
-    ModeData->InternalModeIndex = Index;\r
-    ModeData->HorizontalResolution          = VideoMode->Width;\r
-    ModeData->VerticalResolution            = VideoMode->Height;\r
-    ModeData->ColorDepth                    = VideoMode->ColorDepth;\r
-    ModeData->RefreshRate                   = 60;\r
-    DEBUG ((EFI_D_INFO,\r
-      "Adding Mode %d as Bochs Internal Mode %d: %dx%d, %d-bit, %d Hz\n",\r
-      (INT32) (ModeData - Private->ModeData),\r
-      ModeData->InternalModeIndex,\r
-      ModeData->HorizontalResolution,\r
-      ModeData->VerticalResolution,\r
-      ModeData->ColorDepth,\r
-      ModeData->RefreshRate\r
-      ));\r
-\r
-    ModeData ++ ;\r
+    UINTN RequiredFbSize;\r
+\r
+    ASSERT (VideoMode->ColorDepth % 8 == 0);\r
+    RequiredFbSize = (UINTN) VideoMode->Width * VideoMode->Height *\r
+                     (VideoMode->ColorDepth / 8);\r
+    if (RequiredFbSize <= AvailableFbSize) {\r
+      ModeData->InternalModeIndex    = Index;\r
+      ModeData->HorizontalResolution = VideoMode->Width;\r
+      ModeData->VerticalResolution   = VideoMode->Height;\r
+      ModeData->ColorDepth           = VideoMode->ColorDepth;\r
+      ModeData->RefreshRate          = 60;\r
+      DEBUG ((EFI_D_INFO,\r
+        "Adding Mode %d as Bochs Internal Mode %d: %dx%d, %d-bit, %d Hz\n",\r
+        (INT32) (ModeData - Private->ModeData),\r
+        ModeData->InternalModeIndex,\r
+        ModeData->HorizontalResolution,\r
+        ModeData->VerticalResolution,\r
+        ModeData->ColorDepth,\r
+        ModeData->RefreshRate\r
+        ));\r
+\r
+      ModeData ++ ;\r
+    }\r
     VideoMode ++;\r
   }\r
-  Private->MaxMode = QEMU_VIDEO_BOCHS_MODE_COUNT;\r
+  Private->MaxMode = ModeData - Private->ModeData;\r
 \r
   return EFI_SUCCESS;\r
 }\r