The Power Management Unit on PowerMacs is very sensitive to timeouts during
async message exchanges. It uses rather crude protocol based on a shift
register with an interrupt and is almost continuously exchanging messages with
the host CPU on laptops.
This patch adds a routine to the open_pic driver to be able to select a PMU
driver so that it bumps it's interrupt priority to above the normal level.
This will allow PMU interrupts to occur while another interrupt is pending,
and thus reduce the risk of machine beeing abruptly shutdown by the PMU due to
a timeout in PMU communication caused by excessive interrupt latency. The
problem is very rare, and usually just doesn't happen, but it is still useful
to make things even more robust.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Despite all the care lately in making the powermac sleep/wakeup as
robust as possible, there is still a nasty related to the use of cpufreq
on PMU based machines. Unfortunately, it affects paulus old powerbook
so I have to fix it :)
We didn't manage to understand what is precisely going on, it leads to
memory corruption and might have to do with RAM not beeing properly
refreshed when a cpufreq transition is done right before the sleep.
The best workaround (and less intrusive at this point) we could come up
with is included in this patch. We basically do _not_ force a switch to
high speed on suspend anymore (that is what is causing the problem) on
those machines. We still force a speed switch on wakeup (since we don't
know what speed we are coming back from sleep at, and that seems to work
fine).
Since, during this short interval, the actual CPU speed might be
incorrect, we also hack around by multiplying loops_per_jiffy by 2 (max
speed factor on those machines) during early wakeup stage to make sure
udelay's during that time aren't too short.
For after 2.6.12, we'll change udelay implementation to use the CPU
timebase (which is always constant) instead like we do on ppc64 and thus
get rid of all those problems.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Recent kernels occasionally trigger a PMU timeout on some mac laptops,
typically on wakeup from sleep. This seem to be caused by either a too big
latency caused by the cpufreq switch on wakeup from sleep or by an
interrupt beeing lost due to the reset of the interrupt controller done
during wakeup.
This patch makes that code more robust by stopping PMU auto poll activity
around cpufreq changes on machines that use the PMU for such changes (long
latency switching involving a CPU hard reset and flush of all caches) and
by removing the reset of the open pic interrupt controller on wakeup (that
can cause the loss of an interrupt and Darwin doesn't do it, so it must not
be necessary).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The clock spreading disable/enable code was called to late/early during
the suspend/resume code on some laptops and would trigger a
might_sleep() warning due to the down() call in the low level i2c code.
This fixes it by calling those functions earlier/later when interrupts
are still enabled.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This fixes remaining u32 vs. pm_message_t confusions in -rc2-mm3. [There
are usb changes, too; they went to Greg on his request.]
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This fixes u32 vs. pm_message_t confusion in remaining places. Fortunately
there's few of them.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
