On Wed, 12 Jan 2005 01:41:19 +0000, Linux Kernel Mailing List
<[email protected]> wrote:
> ChangeSet 1.2369, 2005/01/11 17:41:19-08:00, [email protected]
>
> [PATCH] ppc: fix idle with interrupts disabled
>
> The idle-thread-preemption-fix.patch in mm1/2 leads to a stalled box on PPC
> machines which do not provide a powersave function and therefor poll the
> idle loop with interrupts disabled. The patch reenables interrupts.
There is still a stall with PPC boxes that have powersave enabled. I
use a 74xx based board and unless I disable powersave
(ppc_md.power_save=NULL), I get a stall at:
NET: Registered protocol family 2
Reverting default_idle to prepatch form I still see the hang. I think
it is somewhere else in the patchset. Still looking....
Thanks
Brian
On Thu, 13 Jan 2005 15:58:34 -0500, Brian Waite <[email protected]> wrote:
> On Wed, 12 Jan 2005 01:41:19 +0000, Linux Kernel Mailing List
> <[email protected]> wrote:
> > ChangeSet 1.2369, 2005/01/11 17:41:19-08:00, [email protected]
> >
> > [PATCH] ppc: fix idle with interrupts disabled
> >
> > The idle-thread-preemption-fix.patch in mm1/2 leads to a stalled box on PPC
> > machines which do not provide a powersave function and therefor poll the
> > idle loop with interrupts disabled. The patch reenables interrupts.
> There is still a stall with PPC boxes that have powersave enabled. I
> use a 74xx based board and unless I disable powersave
> (ppc_md.power_save=NULL), I get a stall at:
> NET: Registered protocol family 2
>
It looks like the problem has to do with entering the powersave
routine with irqs disabled. Here is a patch that will only enter
powersave if irqs are enabled:
Entering powersave on PPC while irqs are disabled causes a hang. Only
enter powersave if irqs are disabled.
Signed-off-by: Brian Waite <[email protected]>
===== arch/ppc/kernel/idle.c 1.22 vs edited =====
--- 1.22/arch/ppc/kernel/idle.c Tue Jan 11 19:42:36 2005
+++ edited/arch/ppc/kernel/idle.c Thu Jan 13 17:22:25 2005
@@ -39,8 +39,9 @@
powersave = ppc_md.power_save;
if (!need_resched()) {
- if (powersave != NULL)
- powersave();
+ if ((powersave != NULL) && !irqs_disabled())
+ powersave();
+
else {
#ifdef CONFIG_SMP
set_thread_flag(TIF_POLLING_NRFLAG);
I apologize ahead of time for my mailer corrupting the patch. Here is
the patch again attached so as to get whitespace corruption. Also, I
removed a set of excessive parens.
Signed-off-by: Brian Waite <[email protected]>
--- 1.22/arch/ppc/kernel/idle.c Tue Jan 11 19:42:36 2005
+++ edited/arch/ppc/kernel/idle.c Thu Jan 13 17:22:25 2005
@@ -39,8 +39,9 @@
powersave = ppc_md.power_save;
if (!need_resched()) {
- if (powersave != NULL)
- powersave();
+ if (powersave != NULL && !irqs_disabled())
+ powersave();
+
else {
#ifdef CONFIG_SMP
set_thread_flag(TIF_POLLING_NRFLAG);