1 files changed, 55 insertions, 2 deletions

diff --git a/Kernel/Graphics/FramebufferDevice.cpp b/Kernel/Graphics/FramebufferDevice.cpp
index c6d45774cf..fd1bd27277 100644
--- a/Kernel/Graphics/FramebufferDevice.cpp
+++ b/Kernel/Graphics/FramebufferDevice.cpp
@@ -16,6 +16,8 @@
 #include <LibC/errno_numbers.h>
 #include <LibC/sys/ioctl_numbers.h>
 
+#include <Kernel/Panic.h>
+
 namespace Kernel {
 
 KResultOr<Region*> FramebufferDevice::mmap(Process& process, FileDescription&, const Range& range, u64 offset, int prot, bool shared)
@@ -28,16 +30,51 @@ KResultOr<Region*> FramebufferDevice::mmap(Process& process, FileDescription&, c
     if (range.size() != page_round_up(framebuffer_size_in_bytes()))
         return EOVERFLOW;
 
-    auto vmobject = AnonymousVMObject::create_for_physical_range(m_framebuffer_address, framebuffer_size_in_bytes());
+    // FIXME: We rely on the fact that only the WindowServer will mmap the framebuffer
+    // and only once when starting to work with it. If other program wants to do so, we need to fix this.
+    VERIFY(!m_userspace_framebuffer_region);
+    VERIFY(!m_userspace_real_framebuffer_vmobject);
+
+    auto vmobject = AnonymousVMObject::create_for_physical_range(m_framebuffer_address, page_round_up(framebuffer_size_in_bytes()));
     if (!vmobject)
         return ENOMEM;
-    return process.space().allocate_region_with_vmobject(
+    m_userspace_real_framebuffer_vmobject = vmobject;
+
+    auto result = process.space().allocate_region_with_vmobject(
         range,
         vmobject.release_nonnull(),
         0,
         "Framebuffer",
         prot,
         shared);
+    if (!result.is_error()) {
+        m_userspace_framebuffer_region = result.value();
+    }
+    return result;
+}
+
+void FramebufferDevice::dectivate_writes()
+{
+    ScopedSpinLock lock(m_activation_lock);
+    if (!m_userspace_framebuffer_region)
+        return;
+    memcpy(m_swapped_framebuffer_region->vaddr().as_ptr(), m_real_framebuffer_region->vaddr().as_ptr(), page_round_up(framebuffer_size_in_bytes()));
+    auto vmobject = m_swapped_framebuffer_vmobject;
+    m_userspace_framebuffer_region->set_vmobject(vmobject.release_nonnull());
+    m_userspace_framebuffer_region->remap();
+}
+void FramebufferDevice::activate_writes()
+{
+    ScopedSpinLock lock(m_activation_lock);
+    if (!m_userspace_framebuffer_region || !m_real_framebuffer_vmobject)
+        return;
+    // restore the image we had in the void area
+    // FIXME: if we happen to have multiple Framebuffers that are writing to that location
+    // we will experience glitches...
+    memcpy(m_real_framebuffer_region->vaddr().as_ptr(), m_swapped_framebuffer_region->vaddr().as_ptr(), page_round_up(framebuffer_size_in_bytes()));
+    auto vmobject = m_userspace_real_framebuffer_vmobject;
+    m_userspace_framebuffer_region->set_vmobject(vmobject.release_nonnull());
+    m_userspace_framebuffer_region->remap();
 }
 
 String FramebufferDevice::device_name() const
@@ -45,6 +82,18 @@ String FramebufferDevice::device_name() const
     return String::formatted("fb{}", minor());
 }
 
+UNMAP_AFTER_INIT void FramebufferDevice::initialize()
+{
+    m_real_framebuffer_vmobject = AnonymousVMObject::create_for_physical_range(m_framebuffer_address, page_round_up(framebuffer_size_in_bytes()));
+    VERIFY(m_real_framebuffer_vmobject);
+    m_real_framebuffer_region = MM.allocate_kernel_region_with_vmobject(*m_real_framebuffer_vmobject, framebuffer_size_in_bytes(), "Framebuffer", Region::Access::Read | Region::Access::Write);
+    VERIFY(m_real_framebuffer_region);
+    m_swapped_framebuffer_vmobject = AnonymousVMObject::create_with_size(page_round_up(framebuffer_size_in_bytes()), AllocationStrategy::AllocateNow);
+    VERIFY(m_swapped_framebuffer_vmobject);
+    m_swapped_framebuffer_region = MM.allocate_kernel_region_with_vmobject(*m_swapped_framebuffer_vmobject, page_round_up(framebuffer_size_in_bytes()), "Framebuffer Swap (Blank)", Region::Access::Read | Region::Access::Write);
+    VERIFY(m_swapped_framebuffer_region);
+}
+
 UNMAP_AFTER_INIT FramebufferDevice::FramebufferDevice(PhysicalAddress addr, size_t pitch, size_t width, size_t height)
     : BlockDevice(29, GraphicsManagement::the().current_minor_number())
     , m_framebuffer_address(addr)
@@ -52,6 +101,10 @@ UNMAP_AFTER_INIT FramebufferDevice::FramebufferDevice(PhysicalAddress addr, size
     , m_framebuffer_width(width)
     , m_framebuffer_height(height)
 {
+    VERIFY(!m_framebuffer_address.is_null());
+    VERIFY(m_framebuffer_pitch);
+    VERIFY(m_framebuffer_width);
+    VERIFY(m_framebuffer_height);
     dbgln("Framebuffer {}: address={}, pitch={}, width={}, height={}", minor(), addr, pitch, width, height);
 }