libpciaccess-fd-cache.patch is not making sense because it caches the open flag
(read only or write only). If your first call is a read to the config space, it
creates a fd with rdeadonly flag and cache it. Then if you try to write to
config space of the same device, it reuses the same fd and the write call fail
with a EBADF. If you want to cache fd handle, it should be easier to open with
both read and write flags.