Users attempting to enable vfio PCI device assignment with a GPU will often block the default PCI driver from the device to avoid conflicts with the device initialization or release path. This means that vfio-pci is sometimes the first PCI driver to bind to the device. In the case of assigning the primary graphics device, low-level console drivers may still generate resource conflicts. Users often employ kernel command line arguments to disable conflicting drivers or perform unbinding in userspace to avoid this, but the actual solution is often distribution/kernel config specific based on the included drivers.
We can instead allow vfio-pci to copy the behavior of drm_aperture_remove_conflicting_pci_framebuffers() in order to remove these low-level drivers with conflicting resources. vfio-pci is not however a DRM driver, nor does vfio-pci depend on DRM config options, thus we split out and export the necessary DRM apterture support and mirror the framebuffer and VGA support.
I'd be happy to pull this series in through the vfio branch if approved by the DRM maintainers. Thanks,
Alex
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Alex Williamson (2): drm/aperture: Split conflicting platform driver removal vfio/pci: Remove console drivers
drivers/gpu/drm/drm_aperture.c | 33 +++++++++++++++++++++++--------- drivers/vfio/pci/vfio_pci_core.c | 17 ++++++++++++++++ include/drm/drm_aperture.h | 2 ++ 3 files changed, 43 insertions(+), 9 deletions(-)