ladybird/Kernel/BochsVGADevice.cpp
Andreas Kling 443d1c2237 WindowServer: Coordinate double-buffering with the BochsVGA card.
Use the BochsVGA card's virtual-height + virtual-y features to implement
a "hardware double buffering" type scheme.

This is a performance degradation since we now draw a bunch more than before.
But there's also no tearing or cursor flickering. I'm gonna commit this and
try to improve upon it. :^)
2019-02-07 08:56:26 +01:00

70 lines
2.3 KiB
C++

#include <Kernel/BochsVGADevice.h>
#include <Kernel/IO.h>
#include <Kernel/PCI.h>
#define VBE_DISPI_IOPORT_INDEX 0x01CE
#define VBE_DISPI_IOPORT_DATA 0x01CF
#define VBE_DISPI_INDEX_ID 0x0
#define VBE_DISPI_INDEX_XRES 0x1
#define VBE_DISPI_INDEX_YRES 0x2
#define VBE_DISPI_INDEX_BPP 0x3
#define VBE_DISPI_INDEX_ENABLE 0x4
#define VBE_DISPI_INDEX_BANK 0x5
#define VBE_DISPI_INDEX_VIRT_WIDTH 0x6
#define VBE_DISPI_INDEX_VIRT_HEIGHT 0x7
#define VBE_DISPI_INDEX_X_OFFSET 0x8
#define VBE_DISPI_INDEX_Y_OFFSET 0x9
#define VBE_DISPI_DISABLED 0x00
#define VBE_DISPI_ENABLED 0x01
#define VBE_DISPI_LFB_ENABLED 0x40
static BochsVGADevice* s_the;
BochsVGADevice& BochsVGADevice::the()
{
return *s_the;
}
BochsVGADevice::BochsVGADevice()
{
s_the = this;
m_framebuffer_address = PhysicalAddress(find_framebuffer_address());
}
void BochsVGADevice::set_register(word index, word data)
{
IO::out16(VBE_DISPI_IOPORT_INDEX, index);
IO::out16(VBE_DISPI_IOPORT_DATA, data);
}
void BochsVGADevice::set_resolution(int width, int height)
{
set_register(VBE_DISPI_INDEX_ENABLE, VBE_DISPI_DISABLED);
set_register(VBE_DISPI_INDEX_XRES, width);
set_register(VBE_DISPI_INDEX_YRES, height);
set_register(VBE_DISPI_INDEX_VIRT_WIDTH, width);
set_register(VBE_DISPI_INDEX_VIRT_HEIGHT, height * 2);
set_register(VBE_DISPI_INDEX_BPP, 32);
set_register(VBE_DISPI_INDEX_ENABLE, VBE_DISPI_ENABLED | VBE_DISPI_LFB_ENABLED);
set_register(VBE_DISPI_INDEX_BANK, 0);
}
void BochsVGADevice::set_y_offset(int offset)
{
set_register(VBE_DISPI_INDEX_Y_OFFSET, offset);
}
dword BochsVGADevice::find_framebuffer_address()
{
static const PCI::ID bochs_vga_id = { 0x1234, 0x1111 };
static const PCI::ID virtualbox_vga_id = { 0x80ee, 0xbeef };
dword framebuffer_address = 0;
PCI::enumerate_all([&framebuffer_address] (const PCI::Address& address, PCI::ID id) {
if (id == bochs_vga_id || id == virtualbox_vga_id) {
framebuffer_address = PCI::get_BAR0(address) & 0xfffffff0;
kprintf("BochsVGA: framebuffer @ P%x\n", framebuffer_address);
}
});
return framebuffer_address;
}