Hack for detecting _ROM on Lenovo Y470

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c
index 9590f8d..8f955e1 100644
--- a/drivers/gpu/drm/nouveau/nouveau_acpi.c
+++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c
@@ -407,8 +407,11 @@ bool nouveau_acpi_rom_supported(struct pci_dev *pdev)
        return false;

    status = acpi_get_handle(dhandle, "_ROM", &rom_handle);
-   if (ACPI_FAILURE(status))
-       return false;
+   if (ACPI_FAILURE(status)) {
+       status = acpi_get_handle(dhandle, "PEGP._ROM", &rom_handle);
+       if (ACPI_FAILURE(status))
+           return false;
+   }

    nouveau_dsm_priv.rom_handle = rom_handle;
    return true;