[Intel-gfx] [PATCH 0/6] HPD support during suspend.

[Animesh Manna]

Along with below patches sharing some background details/design.
- On BXT, Display cannot generate an interrupt when in D3.
- Without display in D3, S0ix can be achieved, Power impact
will be zero if d3 is blocked. PMCSR for Graphics/Display
is irrelevant, as the power management for them is taken
care by the PUNIT using RC6/DC9 hints and *not* through
PMCSR write trigger.

So solution is based on below principles:
- Display should not be put into D3 for HPD to work.
- With D0+DC9 we can achieve S0ix and at the same time
helps to get the interrupt.
- Using pci_save_state() during suspend to take control
from OSPM and blocking D3, while resuming, giving back
to OSPM by pci_restore_state(). 
- _DSM method is used to program pmc hpd control register
to enable hpd during suspend.

Please have a look and send your comments/suggestions.

Animesh Manna (6):
  drm/i915/bxt: VBT changes for hpd as wakeup feature
  drm/i915/bxt: Added _DSM call to set HPD_CTL.
  drm/i915/bxt: Corrected the guid for bxt.
  drm/i915/bxt: Block D3 during suspend.
  drm/i915: Enable HPD interrupts with master ctl interrupt
  drm/i915/bxt: Enable HPD during suspend.

 drivers/gpu/drm/i915/i915_drv.c       |  6 ++++
 drivers/gpu/drm/i915/i915_drv.h       |  8 +++++
 drivers/gpu/drm/i915/i915_irq.c       | 56 +++++++++++++++++++++++++++++++++--
 drivers/gpu/drm/i915/i915_reg.h       | 13 ++++++++
 drivers/gpu/drm/i915/intel_acpi.c     | 53 ++++++++++++++++++++++++++++-----
 drivers/gpu/drm/i915/intel_bios.c     |  7 +++++
 drivers/gpu/drm/i915/intel_vbt_defs.h |  3 +-
 7 files changed, 134 insertions(+), 12 deletions(-)

-- 
2.0.2