>-----Original Message----- >From: Andrew Morton [mailto:[EMAIL PROTECTED] >Sent: Wednesday, June 06, 2007 6:39 PM >To: Thomas Gleixner >Cc: Pallipadi, Venkatesh; Stable Team; LKML; Len Brown; Ingo >Molnar; Arjan van de Ven; Andi Kleen; Udo A. Steinberg; Dave Jones >Subject: Re: [PATCH] ACPI: Move timer broadcast and pmtimer >access before C3 arbiter shutdown > >On Wed, 06 Jun 2007 11:37:53 +0200 Thomas Gleixner ><[EMAIL PROTECTED]> wrote: > >> From: Udo A. Steinberg <[EMAIL PROTECTED]> >> >> The chip set doc for IHC4 says: >> >> 1.In general, software should not attempt any non-posted >accesses during >> arbiter disable except to the ICH4's power management registers. This >> implies that interrupt handlers for any unmasked hardware >interrupts and >> SMI/NMI should check ARB_DIS status before reading from ICH devices. >> >> So it's not a good idea to access ICH devices after arbiter >shut down. >> >> Signed-off-by: Udo A. Steinberg <[EMAIL PROTECTED]> >> Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]> >> >> --- >> drivers/acpi/processor_idle.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> Index: linux-2.6.22-rc4/drivers/acpi/processor_idle.c >> =================================================================== >> --- linux-2.6.22-rc4.orig/drivers/acpi/processor_idle.c >2007-06-06 11:47:21.000000000 +0200 >> +++ linux-2.6.22-rc4/drivers/acpi/processor_idle.c >2007-06-06 11:48:21.000000000 +0200 >> @@ -488,6 +488,11 @@ static void acpi_processor_idle(void) >> >> case ACPI_STATE_C3: >> >> + /* Get start time (ticks) */ >> + t1 = inl(acpi_gbl_FADT.xpm_timer_block.address); >> + /* Handle timer broadcast before bus arbiter >shutdown ! */ >> + acpi_state_timer_broadcast(pr, cx, 1); >> + >> if (pr->flags.bm_check) { >> if (atomic_inc_return(&c3_cpu_count) == >> num_online_cpus()) { >> @@ -502,10 +507,7 @@ static void acpi_processor_idle(void) >> ACPI_FLUSH_CPU_CACHE(); >> } >> >> - /* Get start time (ticks) */ >> - t1 = inl(acpi_gbl_FADT.xpm_timer_block.address); >> /* Invoke C3 */ >> - acpi_state_timer_broadcast(pr, cx, 1); >> acpi_cstate_enter(cx); >> /* Get end time (ticks) */ >> t2 = inl(acpi_gbl_FADT.xpm_timer_block.address); > >hm, this needs a bit of help to get it to work against Len's >current tree. > >However, if by "non-posted accesses" you're referring to that >inl(), how >come the second one which was left in place isn't also a problem? >
The doc says "except to the ICH4's power management registers". It seems acpi_gbl_FADT.xpm_timer_block.address is actually OK in this case as it is ACPI PM timer register. The problem we had is the access to HPET registers inside acpi_state_timer_broadcast() and that is the one that has to be done before ARB_DIS. Thanks, Venki - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
