drm/i915: Defer enabling rc6 til after we submit the first batch/context
authorChris Wilson <chris@chris-wilson.co.uk>
Wed, 13 Jul 2016 08:10:37 +0000 (09:10 +0100)
committerChris Wilson <chris@chris-wilson.co.uk>
Thu, 14 Jul 2016 14:24:21 +0000 (15:24 +0100)
commitb7137e0cf1e55b5b0cb88fbd85425a1bc0d24c3a
tree7f25a841e2fa7070e293ac358ecbe1780eb30bc8
parent62e1baa128f98006261308182fe3006d66b1bf61
drm/i915: Defer enabling rc6 til after we submit the first batch/context

Some hardware requires a valid render context before it can initiate
rc6 power gating of the GPU; the default state of the GPU is not
sufficient and may lead to undefined behaviour. The first execution of
any batch will load the "golden render state", at which point it is safe
to enable rc6. As we do not forcibly load the kernel context at resume,
we have to hook into the batch submission to be sure that the render
state is setup before enabling rc6.

However, since we don't enable powersaving until that first batch, we
queued a delayed task in order to guarantee that the batch is indeed
submitted.

v2: Rearrange intel_disable_gt_powersave() to match.
v3: Apply user specified cur_freq (or idle_freq if not set).
v4: Give in, and supply a delayed work to autoenable rc6
v5: Mika suggested a couple of better names for delayed_resume_work
v6: Rebalance rpm_put around the autoenable task

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1468397438-21226-7-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
drivers/gpu/drm/i915/i915_drv.c
drivers/gpu/drm/i915/i915_drv.h
drivers/gpu/drm/i915/i915_gem.c
drivers/gpu/drm/i915/intel_display.c
drivers/gpu/drm/i915/intel_drv.h
drivers/gpu/drm/i915/intel_pm.c
drivers/gpu/drm/i915/intel_uncore.c