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>
This patch adds a missing attribute to pmac cpufreq so that
"scaling_available_frequencies" works. It also cleans up the duplicate
definitions for low and high speed constants.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: John Clemens <clemej@alum.rpi.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch updates the PowerMac cpufreq driver. It depends on the addition
of the suspend() method (my previous patch) and on the new flag I defined
to silence some warnings that are normal for us.
It fixes various issues related to cpufreq on pmac, including some crashes
on some models when sleeping the machine while in low speed, proper voltage
control on some newer machines, and adds voltage control on 750FX based G3
laptops.
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>
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!
Benjamin Herrenschmidt