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Kernel: Don't enable write-combine for the Bochs framebuffer device

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While write-combine greatly improves performance on bare metal, QEMU
appears to perform significantly worse when enabling it.
This commit is contained in:
Tom 2022-02-17 20:50:20 -07:00 • committed by Andreas Kling
parent c8aae1ac52
commit 413bc9976c
3 changed files with 9 additions and 2 deletions
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2
Kernel/Graphics/Bochs/GraphicsAdapter.cpp
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@ -127,6 +127,8 @@ UNMAP_AFTER_INIT void BochsGraphicsAdapter::initialize_framebuffer_devices()
{
// FIXME: Find a better way to determine default resolution...
m_framebuffer_device = FramebufferDevice::create(*this, PhysicalAddress(PCI::get_BAR0(pci_address()) & 0xfffffff0), 1024, 768, 1024 * sizeof(u32));
// While write-combine helps greatly on actual hardware, it greatly reduces performance in QEMU
m_framebuffer_device->enable_write_combine(false);
// FIXME: Would be nice to be able to return a ErrorOr<void> here.
VERIFY(!m_framebuffer_device->try_to_initialize().is_error());
}