PCI: Mark AMD/ATI VGA devices that don't reset on D3hot->D0 transition
Some AMD/ATI GPUs report NoSoftRst- to indicate that they perform a reset when software transitions them from D3hot to D0, but there is no apparent effect on the device: the monitor remains synced and the framebuffer contents are retained. Callers of pci_reset_function() don't necessarily have a way to validate whether a reset was effective, so we don't want to rely on NoSoftRst if it's known to be inaccurate. Returning an error in such cases appears to be the better option. For users like vfio-pci, this allows the driver to escalate to the bus reset interfaces. If a device lives on the root bus, there's really no further escalation path, so we exempt PM reset as potentially better than nothing. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Alex Deucher <alexander.deucher@amd.com>
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