[POWERPC] Remove gratuitous reads from powermac pci config space methods
authorNathan Lynch <ntl@pobox.com>
Thu, 9 Aug 2007 21:43:28 +0000 (07:43 +1000)
committerPaul Mackerras <paulus@samba.org>
Fri, 17 Aug 2007 01:01:54 +0000 (11:01 +1000)
commit0f7f2fb85a67953acd6bf379681f22f5c83d4f60
tree1e96f7ae260afdc3cd3c24901e6f03bdcdcb385c
parentb139f1fb0f1e4bfe06f2c88ba8c9a55d9513d871
[POWERPC] Remove gratuitous reads from powermac pci config space methods

The powermac pci configuration space write methods read the written
location immediately after the write is performed, presumably in order
to flush the write.  However, configuration space writes are not
allowed to be posted, making these reads gratuitous.  Furthermore,
this behavior potentially causes us to violate the PCI PM spec when
changing between e.g. D0 and D3 states, because a delay of up to 10ms
may be required before the OS accesses configuration space after the
write which initiates the transition.

Remove the unnecessary reads from macrisc_write_config,
u3_ht_write_config, and u4_pcie_write_config.

Signed-off-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
arch/powerpc/platforms/powermac/pci.c