[Intel-gfx] [PATCH 0/9] Haswell Package C8+

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni at intel.com>

Hi

Here's my next attempt at the Haswell PC8+ feature.

What's new?

 1. I hope I implemented the feedback from Chris. Many function renames, a few
    style changes. Chris' biggest concern was about the interrupts. So in this
    series you'll see patches 2-6 moving some interrupt code around, so all
    changes to each IMR register should go through a single function. With this
    change we can easily detect when someone wants to change IMR but interrupts
    are disabled. As he suggested, we also don't enable the interrupts in that
    case.
 2. Another difference is that now we also disable PC8 when there's GPU work to
    do. The lack of interrupts made things like glxgears work at 2 FPS. I talked
    to Ben about this and what I understood is that the lack of interrupts is
    not really a problem, it just makes things slower. But still I decided to
    write the code to disable PC8 when we have GPU work to do, so background
    apps can run faster than 2 FPS.
 3. Another difference is that now we enable PC8 on a delayed work function that
    only gets called if we stay with 0 refcount for at least 5 seconds. So when
    someone runs "xrandr" we won't enable/disable PC8 dozens of times. Also, on
    "xset dpms force off" we'll only get to PC8 if the desktop environment
    decides to not do rendering every second. Not getting to PC8? Fix your
    desktop environment!
 4. Due to 3 and the fact that Daniel didn't seem to like my "do DP AUX and
    GMBUS without interrupts" approach, the previous patches that implemented
    this just got dropped: we now have the delayed work thing which should
    replace them.
 5. I also added code to wake up from PC8 when doing suspend, we need this.

Despite this, the other thing to discuss is about the size of patch 7. I can
certainly try to split it, but I really think that if all you want is to take a
brief look at the code just and drop some bikesheds, then having a big patch
that implements everything in one piece seems better. I can split this later if
needed. I'm also open to ideas on how to really split this patch. Also notice
that even if the patch is big, it doesn't remove a single line of the current
code. And it adds PC8 disabled by default, so if git bisect points to that patch
the surface to look will be small.

Another thing worth mentioning is that all this code doesn't have IS_HASWELL
checks, and on non-Haswell platforms the refcount will never reach 0, so we
won't ever try to enable PC8. I'm not sure if that's what we want, so please
comment on that.

Even if we decide to delay patch 7, we could try to merge patches 1-6 if they
look acceptable. I'm also not really sure if we want the last patch yet, but
it's there just in case.

Also, I couldn't do i-g-t regression testing since the i-g-t test suite is quite
unreliable on Haswell right now.

Thanks,
Paulo

Paulo Zanoni (9):
  drm/i915: add the FCLK case to intel_ddi_get_cdclk_freq
  drm/i915: wrap GTIMR changes
  drm/i915: wrap GEN6_PMIMR changes
  drm/i915: don't update GEN6_PMIMR when it's not needed
  drm/i915: add dev_priv->pm_irq_mask
  drm/i915: don't disable/reenable IVB error interrupts when not needed
  drm/i915: allow package C8+ states on Haswell (disabled)
  drm/i915: add i915_pc8_status debugfs file
  drm/i915: enable Package C8+ by default

 drivers/gpu/drm/i915/i915_debugfs.c     |  25 ++++
 drivers/gpu/drm/i915/i915_dma.c         |  10 ++
 drivers/gpu/drm/i915/i915_drv.c         |  11 ++
 drivers/gpu/drm/i915/i915_drv.h         |  73 ++++++++++++
 drivers/gpu/drm/i915/i915_irq.c         | 202 +++++++++++++++++++++++++++++---
 drivers/gpu/drm/i915/intel_ddi.c        |   9 +-
 drivers/gpu/drm/i915/intel_display.c    | 164 ++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_dp.c         |   3 +
 drivers/gpu/drm/i915/intel_drv.h        |  14 +++
 drivers/gpu/drm/i915/intel_i2c.c        |   2 +
 drivers/gpu/drm/i915/intel_pm.c         |  13 +-
 drivers/gpu/drm/i915/intel_ringbuffer.c |  32 ++---
 12 files changed, 518 insertions(+), 40 deletions(-)

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1.8.1.2