drm/i915: Make turning on/off PW1 and Misc I/O part of the init/fini sequences
authorDamien Lespiau <damien.lespiau@intel.com>
Wed, 4 Nov 2015 17:24:12 +0000 (19:24 +0200)
committerImre Deak <imre.deak@intel.com>
Tue, 17 Nov 2015 18:43:51 +0000 (20:43 +0200)
commit2f693e28b8df69f67beced5e18bb2b91c2bfcec2
tree07ddc848f50edf0bae5d665e7ece6343291627aa
parentfc17f2274ebe4ef9d7e4a777af8b685f1dd1d584
drm/i915: Make turning on/off PW1 and Misc I/O part of the init/fini sequences

Before this patch, we used the intel_display_power_{get,put} functions
to make sure the PW1 and Misc I/O power wells were enabled all the
time while LCPLL was enabled. We called a get() at
intel_ddi_pll_init() when we discovered that LCPLL was enabled, then
we would call put/get at skl_{un,}init_cdclk().

The problem is that skl_uninit_cdclk() is indirectly called by
intel_runtime_suspend(). So it will only release its power well
_after_ we already decided to runtime suspend. But since we only
decide to runtime suspend after all power wells and refcounts are
released, that basically means we will never decide to runtime
suspend.

So what this patch does to fix that problem is move the PW1 + Misc I/O
power well handling out of the runtime PM mechanism: instead of
calling intel_display_power_{get_put} - functions that touch the
refcount -, we'll call the low level intel_power_well_{en,dis}able,
which don't change the refcount. This way, it is now possible for the
refcount to actually reach zero, and we'll now start runtime
suspending/resuming.

v2 (from Paulo):
  - Write a commit message since the original patch left it empty.
  - Rebase after the intel_power_well_{en,dis}able rename.
  - Use lookup_power_well() instead of hardcoded indexes.

Testcase: igt/pm_rpm/rte (and every other rpm test)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92211
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92605
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446657859-9598-4-git-send-email-imre.deak@intel.com
drivers/gpu/drm/i915/intel_ddi.c
drivers/gpu/drm/i915/intel_display.c
drivers/gpu/drm/i915/intel_drv.h
drivers/gpu/drm/i915/intel_runtime_pm.c