linux/arch/powerpc
Nathan Lynch 1bdb2867e5 [POWERPC] Remove gratuitous reads from maple PCI config space methods
The maple 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.  It definitely causes a system
hang for me with a Broadcom 5721 PCIE network adapter, which is fixed
by this change.

Therefore this removes the gratuitous reads from u3_agp_write_config,
u3_ht_write_config, and u4_pcie_write_config.

Signed-off-by: Nathan Lynch <ntl@pobox.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-08-17 11:01:53 +10:00
..
boot [POWERPC] Fixes to allow use of Ebony's flash chips through physmap_of 2007-08-17 11:01:51 +10:00
configs [POWERPC] Fixes to allow use of Ebony's flash chips through physmap_of 2007-08-17 11:01:51 +10:00
kernel [POWERPC] pseries: Eliminate global error_log_cnt variable 2007-08-17 11:01:52 +10:00
lib Remove fs.h from mm.h 2007-07-29 17:09:29 -07:00
math-emu [POWERPC] ppc math-emu needs -fno-builtin-fabs for math.c and fabs.c 2006-09-26 15:24:35 +10:00
mm [POWERPC] Clean out a bunch of duplicate includes 2007-08-17 11:01:51 +10:00
oprofile Remove fs.h from mm.h 2007-07-29 17:09:29 -07:00
platforms [POWERPC] Remove gratuitous reads from maple PCI config space methods 2007-08-17 11:01:53 +10:00
sysdev [POWERPC] Export DCR symbols for modules 2007-08-17 11:01:52 +10:00
xmon [POWERPC] fix showing xmon help 2007-07-22 21:30:58 +10:00
.gitignore [POWERPC] Add files build to .gitignore 2006-12-04 20:41:29 +11:00
Kconfig [POWERPC] Make endianess of cfg_addr for indirect pci ops runtime 2007-07-23 22:29:09 -05:00
Kconfig.debug Replace CONFIG_SOFTWARE_SUSPEND with CONFIG_HIBERNATION 2007-07-29 16:45:38 -07:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild 2007-07-19 14:28:19 -07:00