![Jesse Barnes](/assets/img/avatar_default.png)
There are several sources of unnecessary power consumption on Intel graphics systems. The first is the LVDS clock. TFTs don't suffer from persistence issues like CRTs, and so we can reduce the LVDS refresh rate when the screen is idle. It will be automatically upclocked when userspace triggers graphical activity. Beyond that, we can enable memory self refresh. This allows the memory to go into a lower power state when the graphics are idle. Finally, we can drop some clocks on the gpu itself. All of these things can be reenabled between frames when GPU activity is triggered, and so there should be no user visible graphical changes. Signed-off-by: Jesse Barnes <jesse.barnes@intel.com> Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Eric Anholt <eric@anholt.net>
204 lines
5.7 KiB
C
204 lines
5.7 KiB
C
/*
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* Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
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* Copyright © 2006-2008 Intel Corporation
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* Jesse Barnes <jesse.barnes@intel.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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* Authors:
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* Eric Anholt <eric@anholt.net>
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*/
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#include <linux/i2c.h>
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#include <linux/i2c-id.h>
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#include <linux/i2c-algo-bit.h>
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#include "drmP.h"
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#include "drm.h"
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#include "intel_drv.h"
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#include "i915_drm.h"
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#include "i915_drv.h"
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void intel_i2c_quirk_set(struct drm_device *dev, bool enable)
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{
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struct drm_i915_private *dev_priv = dev->dev_private;
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/* When using bit bashing for I2C, this bit needs to be set to 1 */
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if (!IS_IGD(dev))
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return;
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if (enable)
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I915_WRITE(DSPCLK_GATE_D,
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I915_READ(DSPCLK_GATE_D) | DPCUNIT_CLOCK_GATE_DISABLE);
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else
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I915_WRITE(DSPCLK_GATE_D,
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I915_READ(DSPCLK_GATE_D) & (~DPCUNIT_CLOCK_GATE_DISABLE));
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}
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/*
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* Intel GPIO access functions
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*/
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#define I2C_RISEFALL_TIME 20
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static int get_clock(void *data)
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{
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struct intel_i2c_chan *chan = data;
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struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
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u32 val;
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val = I915_READ(chan->reg);
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return ((val & GPIO_CLOCK_VAL_IN) != 0);
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}
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static int get_data(void *data)
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{
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struct intel_i2c_chan *chan = data;
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struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
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u32 val;
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val = I915_READ(chan->reg);
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return ((val & GPIO_DATA_VAL_IN) != 0);
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}
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static void set_clock(void *data, int state_high)
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{
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struct intel_i2c_chan *chan = data;
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struct drm_device *dev = chan->drm_dev;
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struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
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u32 reserved = 0, clock_bits;
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/* On most chips, these bits must be preserved in software. */
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if (!IS_I830(dev) && !IS_845G(dev))
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reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
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GPIO_CLOCK_PULLUP_DISABLE);
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if (state_high)
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clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
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else
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clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
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GPIO_CLOCK_VAL_MASK;
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I915_WRITE(chan->reg, reserved | clock_bits);
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udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
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}
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static void set_data(void *data, int state_high)
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{
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struct intel_i2c_chan *chan = data;
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struct drm_device *dev = chan->drm_dev;
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struct drm_i915_private *dev_priv = chan->drm_dev->dev_private;
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u32 reserved = 0, data_bits;
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/* On most chips, these bits must be preserved in software. */
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if (!IS_I830(dev) && !IS_845G(dev))
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reserved = I915_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
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GPIO_CLOCK_PULLUP_DISABLE);
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if (state_high)
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data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
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else
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data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
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GPIO_DATA_VAL_MASK;
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I915_WRITE(chan->reg, reserved | data_bits);
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udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
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}
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/**
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* intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
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* @dev: DRM device
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* @output: driver specific output device
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* @reg: GPIO reg to use
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* @name: name for this bus
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* @slave_addr: slave address (if fixed)
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*
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* Creates and registers a new i2c bus with the Linux i2c layer, for use
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* in output probing and control (e.g. DDC or SDVO control functions).
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*
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* Possible values for @reg include:
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* %GPIOA
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* %GPIOB
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* %GPIOC
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* %GPIOD
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* %GPIOE
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* %GPIOF
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* %GPIOG
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* %GPIOH
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* see PRM for details on how these different busses are used.
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*/
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struct i2c_adapter *intel_i2c_create(struct drm_device *dev, const u32 reg,
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const char *name)
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{
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struct intel_i2c_chan *chan;
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chan = kzalloc(sizeof(struct intel_i2c_chan), GFP_KERNEL);
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if (!chan)
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goto out_free;
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chan->drm_dev = dev;
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chan->reg = reg;
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snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
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chan->adapter.owner = THIS_MODULE;
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chan->adapter.algo_data = &chan->algo;
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chan->adapter.dev.parent = &dev->pdev->dev;
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chan->algo.setsda = set_data;
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chan->algo.setscl = set_clock;
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chan->algo.getsda = get_data;
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chan->algo.getscl = get_clock;
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chan->algo.udelay = 20;
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chan->algo.timeout = usecs_to_jiffies(2200);
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chan->algo.data = chan;
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i2c_set_adapdata(&chan->adapter, chan);
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if(i2c_bit_add_bus(&chan->adapter))
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goto out_free;
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/* JJJ: raise SCL and SDA? */
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intel_i2c_quirk_set(dev, true);
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set_data(chan, 1);
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set_clock(chan, 1);
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intel_i2c_quirk_set(dev, false);
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udelay(20);
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return &chan->adapter;
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out_free:
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kfree(chan);
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return NULL;
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}
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/**
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* intel_i2c_destroy - unregister and free i2c bus resources
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* @output: channel to free
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*
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* Unregister the adapter from the i2c layer, then free the structure.
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*/
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void intel_i2c_destroy(struct i2c_adapter *adapter)
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{
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struct intel_i2c_chan *chan;
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if (!adapter)
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return;
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chan = container_of(adapter,
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struct intel_i2c_chan,
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adapter);
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i2c_del_adapter(&chan->adapter);
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kfree(chan);
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}
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