Intel Framebuffer Display Driver

This is a simple display driver for Intel GPUs that uses the framebuffer configured by the bootloader. It is intended for early-boot use before intel-display is available.

Manual testing

We do not currently have automated integration tests. Behavior changes in this driver must be validated using this manual test.

Start with a supported Intel device.

Replace the PCI device IDs from src/graphics/display/drivers/intel-display/meta/intel-display.bind with 0xFFFF so the display device won't bind to intel-display:

primary parent "pci" {
  fuchsia.Service == "fuchsia.hardware.pci.Service";
  fuchsia.BIND_PCI_VID == fuchsia.pci.BIND_PCI_VID.INTEL;

  accept fuchsia.BIND_PCI_DID {
    0xFFFF, // Only keep a placeholder. No Intel display device will bind to this driver.
  }
}

Remove the rejected PCI device IDs from the framebuffer driver bind rules in src/graphics/display/drivers/framebuffer-intel-display/meta/framebuffer-intel-display.bind:

primary parent "pci" {
  fuchsia.Service == "fuchsia.hardware.pci.Service";
  fuchsia.BIND_PCI_VID == fuchsia.pci.BIND_PCI_VID.INTEL;
  fuchsia.BIND_PCI_CLASS == fuchsia.pci.BIND_PCI_CLASS.DISPLAY;

  // The rejected PCI device list is removed.
}

Build Fuchsia, and flash or OTA the target.
```
fx build
ffx target flash # or `fx ota`
```
Launch the squares demo in the display-tool test utility.
```
ffx target ssh -- display-tool squares
```
Add the following footer to your CL description, to document having performed the test.
```
Test: ffx target ssh -- display-tool squares
```

These instructions will work with a workbench_eng.x64 build that includes the //src/graphics/display:tools GN target. The //src/graphics/display:tests target is also recommended, as it builds the automated unit tests. Debug assertions, which are extensively used in display drivers, are only enabled in debug builds.

fx set workbench_eng.x64 --debug --with //src/graphics/display:tools \
    --with //src/graphics/display:tests