1. 10 Jun, 2005 1 commit
    • Benjamin Herrenschmidt's avatar
      [PATCH] ppc32: Fix nasty sleep/wakeup problem · 0086b5ec
      Benjamin Herrenschmidt authored
      
      
      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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      0086b5ec
  2. 09 Jun, 2005 18 commits
  3. 08 Jun, 2005 21 commits