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Commit 862372bc authored by Ville Syrjälä's avatar Ville Syrjälä
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drm/i915: GMBUS don't need no forcewake 



GMBUS is part of the display engine, and thus has no need for
forcewake. Let's not bother trying to grab it then.

I don't recall if the display engine suffers from system hangs
due to multiple accesses to the same "cacheline" in mmio space.
I hope not since we're no longer protected by the uncore lock
since commit 4e6c2d58 ("drm/i915: Take forcewake once for
the entire GMBUS transaction")

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Weinehall <david.weinehall@linux.intel.com>
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1476272687-15070-1-git-send-email-ville.syrjala@linux.intel.com


Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent 06a75ace

drivers/gpu/drm/i915/intel_i2c.c

+0 −5
Original line number Diff line number Diff line
@@ -467,13 +467,9 @@ do_gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) 
					       struct intel_gmbus,

					       adapter);

	struct drm_i915_private *dev_priv = bus->dev_priv;

	const unsigned int fw =

		intel_uncore_forcewake_for_reg(dev_priv, GMBUS0,

					       FW_REG_READ | FW_REG_WRITE);

	int i = 0, inc, try = 0;

	int ret = 0;



	intel_uncore_forcewake_get(dev_priv, fw);

retry:

	I915_WRITE_FW(GMBUS0, bus->reg0);
@@ -575,7 +571,6 @@ do_gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) 
	ret = -EAGAIN;



out:

	intel_uncore_forcewake_put(dev_priv, fw);

	return ret;

}