/* i915_drv.c -- i830,i845,i855,i865,i915 driver -*- linux-c -*-
 */
/*
 *
 * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

#include <linux/device.h>
#include "drmP.h"
#include "drm.h"
#include "i915_drm.h"
#include "i915_drv.h"
#include "intel_drv.h"

#include <linux/console.h>
#include <linux/module.h>
#include "drm_crtc_helper.h"

static int i915_modeset __read_mostly = -1;
module_param_named(modeset, i915_modeset, int, 0400);
MODULE_PARM_DESC(modeset,
		"Use kernel modesetting [KMS] (0=DRM_I915_KMS from .config, "
		"1=on, -1=force vga console preference [default])");

unsigned int i915_fbpercrtc __always_unused = 0;
module_param_named(fbpercrtc, i915_fbpercrtc, int, 0400);

int i915_panel_ignore_lid __read_mostly = 0;
module_param_named(panel_ignore_lid, i915_panel_ignore_lid, int, 0600);
MODULE_PARM_DESC(panel_ignore_lid,
		"Override lid status (0=autodetect [default], 1=lid open, "
		"-1=lid closed)");

unsigned int i915_powersave __read_mostly = 1;
module_param_named(powersave, i915_powersave, int, 0600);
MODULE_PARM_DESC(powersave,
		"Enable powersavings, fbc, downclocking, etc. (default: true)");

unsigned int i915_semaphores __read_mostly = 0;
module_param_named(semaphores, i915_semaphores, int, 0600);
MODULE_PARM_DESC(semaphores,
		"Use semaphores for inter-ring sync (default: false)");

unsigned int i915_enable_rc6 __read_mostly = 0;
module_param_named(i915_enable_rc6, i915_enable_rc6, int, 0600);
MODULE_PARM_DESC(i915_enable_rc6,
		"Enable power-saving render C-state 6 (default: true)");

unsigned int i915_enable_fbc __read_mostly = -1;
module_param_named(i915_enable_fbc, i915_enable_fbc, int, 0600);
MODULE_PARM_DESC(i915_enable_fbc,
		"Enable frame buffer compression for power savings "
		"(default: -1 (use per-chip default))");

unsigned int i915_lvds_downclock __read_mostly = 0;
module_param_named(lvds_downclock, i915_lvds_downclock, int, 0400);
MODULE_PARM_DESC(lvds_downclock,
		"Use panel (LVDS/eDP) downclocking for power savings "
		"(default: false)");

unsigned int i915_panel_use_ssc __read_mostly = -1;
module_param_named(lvds_use_ssc, i915_panel_use_ssc, int, 0600);
MODULE_PARM_DESC(lvds_use_ssc,
		"Use Spread Spectrum Clock with panels [LVDS/eDP] "
		"(default: auto from VBT)");

int i915_vbt_sdvo_panel_type __read_mostly = -1;
module_param_named(vbt_sdvo_panel_type, i915_vbt_sdvo_panel_type, int, 0600);
MODULE_PARM_DESC(vbt_sdvo_panel_type,
		"Override selection of SDVO panel mode in the VBT "
		"(default: auto)");

static bool i915_try_reset __read_mostly = true;
module_param_named(reset, i915_try_reset, bool, 0600);
MODULE_PARM_DESC(reset, "Attempt GPU resets (default: true)");

bool i915_enable_hangcheck __read_mostly = true;
module_param_named(enable_hangcheck, i915_enable_hangcheck, bool, 0644);
MODULE_PARM_DESC(enable_hangcheck,
		"Periodically check GPU activity for detecting hangs. "
		"WARNING: Disabling this can cause system wide hangs. "
		"(default: true)");

static struct drm_driver driver;
extern int intel_agp_enabled;

#define INTEL_VGA_DEVICE(id, info) {		\
	.class = PCI_CLASS_DISPLAY_VGA << 8,	\
	.class_mask = 0xff0000,			\
	.vendor = 0x8086,			\
	.device = id,				\
	.subvendor = PCI_ANY_ID,		\
	.subdevice = PCI_ANY_ID,		\
	.driver_data = (unsigned long) info }

static const struct intel_device_info intel_i830_info = {
	.gen = 2, .is_mobile = 1, .cursor_needs_physical = 1,
	.has_overlay = 1, .overlay_needs_physical = 1,
};

static const struct intel_device_info intel_845g_info = {
	.gen = 2,
	.has_overlay = 1, .overlay_needs_physical = 1,
};

static const struct intel_device_info intel_i85x_info = {
	.gen = 2, .is_i85x = 1, .is_mobile = 1,
	.cursor_needs_physical = 1,
	.has_overlay = 1, .overlay_needs_physical = 1,
};

static const struct intel_device_info intel_i865g_info = {
	.gen = 2,
	.has_overlay = 1, .overlay_needs_physical = 1,
};

static const struct intel_device_info intel_i915g_info = {
	.gen = 3, .is_i915g = 1, .cursor_needs_physical = 1,
	.has_overlay = 1, .overlay_needs_physical = 1,
};
static const struct intel_device_info intel_i915gm_info = {
	.gen = 3, .is_mobile = 1,
	.cursor_needs_physical = 1,
	.has_overlay = 1, .overlay_needs_physical = 1,
	.supports_tv = 1,
};
static const struct intel_device_info intel_i945g_info = {
	.gen = 3, .has_hotplug = 1, .cursor_needs_physical = 1,
	.has_overlay = 1, .overlay_needs_physical = 1,
};
static const struct intel_device_info intel_i945gm_info = {
	.gen = 3, .is_i945gm = 1, .is_mobile = 1,
	.has_hotplug = 1, .cursor_needs_physical = 1,
	.has_overlay = 1, .overlay_needs_physical = 1,
	.supports_tv = 1,
};

static const struct intel_device_info intel_i965g_info = {
	.gen = 4, .is_broadwater = 1,
	.has_hotplug = 1,
	.has_overlay = 1,
};

static const struct intel_device_info intel_i965gm_info = {
	.gen = 4, .is_crestline = 1,
	.is_mobile = 1, .has_fbc = 1, .has_hotplug = 1,
	.has_overlay = 1,
	.supports_tv = 1,
};

static const struct intel_device_info intel_g33_info = {
	.gen = 3, .is_g33 = 1,
	.need_gfx_hws = 1, .has_hotplug = 1,
	.has_overlay = 1,
};

static const struct intel_device_info intel_g45_info = {
	.gen = 4, .is_g4x = 1, .need_gfx_hws = 1,
	.has_pipe_cxsr = 1, .has_hotplug = 1,
	.has_bsd_ring = 1,
};

static const struct intel_device_info intel_gm45_info = {
	.gen = 4, .is_g4x = 1,
	.is_mobile = 1, .need_gfx_hws = 1, .has_fbc = 1,
	.has_pipe_cxsr = 1, .has_hotplug = 1,
	.supports_tv = 1,
	.has_bsd_ring = 1,
};

static const struct intel_device_info intel_pineview_info = {
	.gen = 3, .is_g33 = 1, .is_pineview = 1, .is_mobile = 1,
	.need_gfx_hws = 1, .has_hotplug = 1,
	.has_overlay = 1,
};

static const struct intel_device_info intel_ironlake_d_info = {
	.gen = 5,
	.need_gfx_hws = 1, .has_pipe_cxsr = 1, .has_hotplug = 1,
	.has_bsd_ring = 1,
};

static const struct intel_device_info intel_ironlake_m_info = {
	.gen = 5, .is_mobile = 1,
	.need_gfx_hws = 1, .has_hotplug = 1,
	.has_fbc = 1,
	.has_bsd_ring = 1,
};

static const struct intel_device_info intel_sandybridge_d_info = {
	.gen = 6,
	.need_gfx_hws = 1, .has_hotplug = 1,
	.has_bsd_ring = 1,
	.has_blt_ring = 1,
};

static const struct intel_device_info intel_sandybridge_m_info = {
	.gen = 6, .is_mobile = 1,
	.need_gfx_hws = 1, .has_hotplug = 1,
	.has_fbc = 1,
	.has_bsd_ring = 1,
	.has_blt_ring = 1,
};

static const struct intel_device_info intel_ivybridge_d_info = {
	.is_ivybridge = 1, .gen = 7,
	.need_gfx_hws = 1, .has_hotplug = 1,
	.has_bsd_ring = 1,
	.has_blt_ring = 1,
};

static const struct intel_device_info intel_ivybridge_m_info = {
	.is_ivybridge = 1, .gen = 7, .is_mobile = 1,
	.need_gfx_hws = 1, .has_hotplug = 1,
	.has_fbc = 0,	/* FBC is not enabled on Ivybridge mobile yet */
	.has_bsd_ring = 1,
	.has_blt_ring = 1,
};

static const struct pci_device_id pciidlist[] = {		/* aka */
	INTEL_VGA_DEVICE(0x3577, &intel_i830_info),		/* I830_M */
	INTEL_VGA_DEVICE(0x2562, &intel_845g_info),		/* 845_G */
	INTEL_VGA_DEVICE(0x3582, &intel_i85x_info),		/* I855_GM */
	INTEL_VGA_DEVICE(0x358e, &intel_i85x_info),
	INTEL_VGA_DEVICE(0x2572, &intel_i865g_info),		/* I865_G */
	INTEL_VGA_DEVICE(0x2582, &intel_i915g_info),		/* I915_G */
	INTEL_VGA_DEVICE(0x258a, &intel_i915g_info),		/* E7221_G */
	INTEL_VGA_DEVICE(0x2592, &intel_i915gm_info),		/* I915_GM */
	INTEL_VGA_DEVICE(0x2772, &intel_i945g_info),		/* I945_G */
	INTEL_VGA_DEVICE(0x27a2, &intel_i945gm_info),		/* I945_GM */
	INTEL_VGA_DEVICE(0x27ae, &intel_i945gm_info),		/* I945_GME */
	INTEL_VGA_DEVICE(0x2972, &intel_i965g_info),		/* I946_GZ */
	INTEL_VGA_DEVICE(0x2982, &intel_i965g_info),		/* G35_G */
	INTEL_VGA_DEVICE(0x2992, &intel_i965g_info),		/* I965_Q */
	INTEL_VGA_DEVICE(0x29a2, &intel_i965g_info),		/* I965_G */
	INTEL_VGA_DEVICE(0x29b2, &intel_g33_info),		/* Q35_G */
	INTEL_VGA_DEVICE(0x29c2, &intel_g33_info),		/* G33_G */
	INTEL_VGA_DEVICE(0x29d2, &intel_g33_info),		/* Q33_G */
	INTEL_VGA_DEVICE(0x2a02, &intel_i965gm_info),		/* I965_GM */
	INTEL_VGA_DEVICE(0x2a12, &intel_i965gm_info),		/* I965_GME */
	INTEL_VGA_DEVICE(0x2a42, &intel_gm45_info),		/* GM45_G */
	INTEL_VGA_DEVICE(0x2e02, &intel_g45_info),		/* IGD_E_G */
	INTEL_VGA_DEVICE(0x2e12, &intel_g45_info),		/* Q45_G */
	INTEL_VGA_DEVICE(0x2e22, &intel_g45_info),		/* G45_G */
	INTEL_VGA_DEVICE(0x2e32, &intel_g45_info),		/* G41_G */
	INTEL_VGA_DEVICE(0x2e42, &intel_g45_info),		/* B43_G */
	INTEL_VGA_DEVICE(0x2e92, &intel_g45_info),		/* B43_G.1 */
	INTEL_VGA_DEVICE(0xa001, &intel_pineview_info),
	INTEL_VGA_DEVICE(0xa011, &intel_pineview_info),
	INTEL_VGA_DEVICE(0x0042, &intel_ironlake_d_info),
	INTEL_VGA_DEVICE(0x0046, &intel_ironlake_m_info),
	INTEL_VGA_DEVICE(0x0102, &intel_sandybridge_d_info),
	INTEL_VGA_DEVICE(0x0112, &intel_sandybridge_d_info),
	INTEL_VGA_DEVICE(0x0122, &intel_sandybridge_d_info),
	INTEL_VGA_DEVICE(0x0106, &intel_sandybridge_m_info),
	INTEL_VGA_DEVICE(0x0116, &intel_sandybridge_m_info),
	INTEL_VGA_DEVICE(0x0126, &intel_sandybridge_m_info),
	INTEL_VGA_DEVICE(0x010A, &intel_sandybridge_d_info),
	INTEL_VGA_DEVICE(0x0156, &intel_ivybridge_m_info), /* GT1 mobile */
	INTEL_VGA_DEVICE(0x0166, &intel_ivybridge_m_info), /* GT2 mobile */
	INTEL_VGA_DEVICE(0x0152, &intel_ivybridge_d_info), /* GT1 desktop */
	INTEL_VGA_DEVICE(0x0162, &intel_ivybridge_d_info), /* GT2 desktop */
	INTEL_VGA_DEVICE(0x015a, &intel_ivybridge_d_info), /* GT1 server */
	{0, 0, 0}
};

#if defined(CONFIG_DRM_I915_KMS)
MODULE_DEVICE_TABLE(pci, pciidlist);
#endif

#define INTEL_PCH_DEVICE_ID_MASK	0xff00
#define INTEL_PCH_IBX_DEVICE_ID_TYPE	0x3b00
#define INTEL_PCH_CPT_DEVICE_ID_TYPE	0x1c00
#define INTEL_PCH_PPT_DEVICE_ID_TYPE	0x1e00

void intel_detect_pch(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct pci_dev *pch;

	/*
	 * The reason to probe ISA bridge instead of Dev31:Fun0 is to
	 * make graphics device passthrough work easy for VMM, that only
	 * need to expose ISA bridge to let driver know the real hardware
	 * underneath. This is a requirement from virtualization team.
	 */
	pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
	if (pch) {
		if (pch->vendor == PCI_VENDOR_ID_INTEL) {
			int id;
			id = pch->device & INTEL_PCH_DEVICE_ID_MASK;

			if (id == INTEL_PCH_IBX_DEVICE_ID_TYPE) {
				dev_priv->pch_type = PCH_IBX;
				DRM_DEBUG_KMS("Found Ibex Peak PCH\n");
			} else if (id == INTEL_PCH_CPT_DEVICE_ID_TYPE) {
				dev_priv->pch_type = PCH_CPT;
				DRM_DEBUG_KMS("Found CougarPoint PCH\n");
			} else if (id == INTEL_PCH_PPT_DEVICE_ID_TYPE) {
				/* PantherPoint is CPT compatible */
				dev_priv->pch_type = PCH_CPT;
				DRM_DEBUG_KMS("Found PatherPoint PCH\n");
			}
		}
		pci_dev_put(pch);
	}
}

static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
{
	int count;

	count = 0;
	while (count++ < 50 && (I915_READ_NOTRACE(FORCEWAKE_ACK) & 1))
		udelay(10);

	I915_WRITE_NOTRACE(FORCEWAKE, 1);
	POSTING_READ(FORCEWAKE);

	count = 0;
	while (count++ < 50 && (I915_READ_NOTRACE(FORCEWAKE_ACK) & 1) == 0)
		udelay(10);
}

/*
 * Generally this is called implicitly by the register read function. However,
 * if some sequence requires the GT to not power down then this function should
 * be called at the beginning of the sequence followed by a call to
 * gen6_gt_force_wake_put() at the end of the sequence.
 */
void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
{
	WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));

	/* Forcewake is atomic in case we get in here without the lock */
	if (atomic_add_return(1, &dev_priv->forcewake_count) == 1)
		__gen6_gt_force_wake_get(dev_priv);
}

static void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
{
	I915_WRITE_NOTRACE(FORCEWAKE, 0);
	POSTING_READ(FORCEWAKE);
}

/*
 * see gen6_gt_force_wake_get()
 */
void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
{
	WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));

	if (atomic_dec_and_test(&dev_priv->forcewake_count))
		__gen6_gt_force_wake_put(dev_priv);
}

void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv)
{
	if (dev_priv->gt_fifo_count < GT_FIFO_NUM_RESERVED_ENTRIES) {
		int loop = 500;
		u32 fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES);
		while (fifo <= GT_FIFO_NUM_RESERVED_ENTRIES && loop--) {
			udelay(10);
			fifo = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES);
		}
		WARN_ON(loop < 0 && fifo <= GT_FIFO_NUM_RESERVED_ENTRIES);
		dev_priv->gt_fifo_count = fifo;
	}
	dev_priv->gt_fifo_count--;
}

static int i915_drm_freeze(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;

	drm_kms_helper_poll_disable(dev);

	pci_save_state(dev->pdev);

	/* If KMS is active, we do the leavevt stuff here */
	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
		int error = i915_gem_idle(dev);
		if (error) {
			dev_err(&dev->pdev->dev,
				"GEM idle failed, resume might fail\n");
			return error;
		}
		drm_irq_uninstall(dev);
	}

	i915_save_state(dev);

	intel_opregion_fini(dev);

	/* Modeset on resume, not lid events */
	dev_priv->modeset_on_lid = 0;

	return 0;
}

int i915_suspend(struct drm_device *dev, pm_message_t state)
{
	int error;

	if (!dev || !dev->dev_private) {
		DRM_ERROR("dev: %p\n", dev);
		DRM_ERROR("DRM not initialized, aborting suspend.\n");
		return -ENODEV;
	}

	if (state.event == PM_EVENT_PRETHAW)
		return 0;


	if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
		return 0;

	error = i915_drm_freeze(dev);
	if (error)
		return error;

	if (state.event == PM_EVENT_SUSPEND) {
		/* Shut down the device */
		pci_disable_device(dev->pdev);
		pci_set_power_state(dev->pdev, PCI_D3hot);
	}

	return 0;
}

static int i915_drm_thaw(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	int error = 0;

	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
		mutex_lock(&dev->struct_mutex);
		i915_gem_restore_gtt_mappings(dev);
		mutex_unlock(&dev->struct_mutex);
	}

	i915_restore_state(dev);
	intel_opregion_setup(dev);

	/* KMS EnterVT equivalent */
	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
		mutex_lock(&dev->struct_mutex);
		dev_priv->mm.suspended = 0;

		error = i915_gem_init_ringbuffer(dev);
		mutex_unlock(&dev->struct_mutex);

		if (HAS_PCH_SPLIT(dev))
			ironlake_init_pch_refclk(dev);

		drm_mode_config_reset(dev);
		drm_irq_install(dev);

		/* Resume the modeset for every activated CRTC */
		drm_helper_resume_force_mode(dev);

		if (IS_IRONLAKE_M(dev))
			ironlake_enable_rc6(dev);
	}

	intel_opregion_init(dev);

	dev_priv->modeset_on_lid = 0;

	return error;
}

int i915_resume(struct drm_device *dev)
{
	int ret;

	if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
		return 0;

	if (pci_enable_device(dev->pdev))
		return -EIO;

	pci_set_master(dev->pdev);

	ret = i915_drm_thaw(dev);
	if (ret)
		return ret;

	drm_kms_helper_poll_enable(dev);
	return 0;
}

static int i8xx_do_reset(struct drm_device *dev, u8 flags)
{
	struct drm_i915_private *dev_priv = dev->dev_private;

	if (IS_I85X(dev))
		return -ENODEV;

	I915_WRITE(D_STATE, I915_READ(D_STATE) | DSTATE_GFX_RESET_I830);
	POSTING_READ(D_STATE);

	if (IS_I830(dev) || IS_845G(dev)) {
		I915_WRITE(DEBUG_RESET_I830,
			   DEBUG_RESET_DISPLAY |
			   DEBUG_RESET_RENDER |
			   DEBUG_RESET_FULL);
		POSTING_READ(DEBUG_RESET_I830);
		msleep(1);

		I915_WRITE(DEBUG_RESET_I830, 0);
		POSTING_READ(DEBUG_RESET_I830);
	}

	msleep(1);

	I915_WRITE(D_STATE, I915_READ(D_STATE) & ~DSTATE_GFX_RESET_I830);
	POSTING_READ(D_STATE);

	return 0;
}

static int i965_reset_complete(struct drm_device *dev)
{
	u8 gdrst;
	pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);
	return gdrst & 0x1;
}

static int i965_do_reset(struct drm_device *dev, u8 flags)
{
	u8 gdrst;

	/*
	 * Set the domains we want to reset (GRDOM/bits 2 and 3) as
	 * well as the reset bit (GR/bit 0).  Setting the GR bit
	 * triggers the reset; when done, the hardware will clear it.
	 */
	pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);
	pci_write_config_byte(dev->pdev, I965_GDRST, gdrst | flags | 0x1);

	return wait_for(i965_reset_complete(dev), 500);
}

static int ironlake_do_reset(struct drm_device *dev, u8 flags)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	u32 gdrst = I915_READ(MCHBAR_MIRROR_BASE + ILK_GDSR);
	I915_WRITE(MCHBAR_MIRROR_BASE + ILK_GDSR, gdrst | flags | 0x1);
	return wait_for(I915_READ(MCHBAR_MIRROR_BASE + ILK_GDSR) & 0x1, 500);
}

static int gen6_do_reset(struct drm_device *dev, u8 flags)
{
	struct drm_i915_private *dev_priv = dev->dev_private;

	I915_WRITE(GEN6_GDRST, GEN6_GRDOM_FULL);
	return wait_for((I915_READ(GEN6_GDRST) & GEN6_GRDOM_FULL) == 0, 500);
}

/**
 * i965_reset - reset chip after a hang
 * @dev: drm device to reset
 * @flags: reset domains
 *
 * Reset the chip.  Useful if a hang is detected. Returns zero on successful
 * reset or otherwise an error code.
 *
 * Procedure is fairly simple:
 *   - reset the chip using the reset reg
 *   - re-init context state
 *   - re-init hardware status page
 *   - re-init ring buffer
 *   - re-init interrupt state
 *   - re-init display
 */
int i915_reset(struct drm_device *dev, u8 flags)
{
	drm_i915_private_t *dev_priv = dev->dev_private;
	/*
	 * We really should only reset the display subsystem if we actually
	 * need to
	 */
	bool need_display = true;
	int ret;

	if (!i915_try_reset)
		return 0;

	if (!mutex_trylock(&dev->struct_mutex))
		return -EBUSY;

	i915_gem_reset(dev);

	ret = -ENODEV;
	if (get_seconds() - dev_priv->last_gpu_reset < 5) {
		DRM_ERROR("GPU hanging too fast, declaring wedged!\n");
	} else switch (INTEL_INFO(dev)->gen) {
	case 7:
	case 6:
		ret = gen6_do_reset(dev, flags);
		/* If reset with a user forcewake, try to restore */
		if (atomic_read(&dev_priv->forcewake_count))
			__gen6_gt_force_wake_get(dev_priv);
		break;
	case 5:
		ret = ironlake_do_reset(dev, flags);
		break;
	case 4:
		ret = i965_do_reset(dev, flags);
		break;
	case 2:
		ret = i8xx_do_reset(dev, flags);
		break;
	}
	dev_priv->last_gpu_reset = get_seconds();
	if (ret) {
		DRM_ERROR("Failed to reset chip.\n");
		mutex_unlock(&dev->struct_mutex);
		return ret;
	}

	/* Ok, now get things going again... */

	/*
	 * Everything depends on having the GTT running, so we need to start
	 * there.  Fortunately we don't need to do this unless we reset the
	 * chip at a PCI level.
	 *
	 * Next we need to restore the context, but we don't use those
	 * yet either...
	 *
	 * Ring buffer needs to be re-initialized in the KMS case, or if X
	 * was running at the time of the reset (i.e. we weren't VT
	 * switched away).
	 */
	if (drm_core_check_feature(dev, DRIVER_MODESET) ||
			!dev_priv->mm.suspended) {
		dev_priv->mm.suspended = 0;

		dev_priv->ring[RCS].init(&dev_priv->ring[RCS]);
		if (HAS_BSD(dev))
		    dev_priv->ring[VCS].init(&dev_priv->ring[VCS]);
		if (HAS_BLT(dev))
		    dev_priv->ring[BCS].init(&dev_priv->ring[BCS]);

		mutex_unlock(&dev->struct_mutex);
		drm_irq_uninstall(dev);
		drm_mode_config_reset(dev);
		drm_irq_install(dev);
		mutex_lock(&dev->struct_mutex);
	}

	mutex_unlock(&dev->struct_mutex);

	/*
	 * Perform a full modeset as on later generations, e.g. Ironlake, we may
	 * need to retrain the display link and cannot just restore the register
	 * values.
	 */
	if (need_display) {
		mutex_lock(&dev->mode_config.mutex);
		drm_helper_resume_force_mode(dev);
		mutex_unlock(&dev->mode_config.mutex);
	}

	return 0;
}


static int __devinit
i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
{
	/* Only bind to function 0 of the device. Early generations
	 * used function 1 as a placeholder for multi-head. This causes
	 * us confusion instead, especially on the systems where both
	 * functions have the same PCI-ID!
	 */
	if (PCI_FUNC(pdev->devfn))
		return -ENODEV;

	return drm_get_pci_dev(pdev, ent, &driver);
}

static void
i915_pci_remove(struct pci_dev *pdev)
{
	struct drm_device *dev = pci_get_drvdata(pdev);

	drm_put_dev(dev);
}

static int i915_pm_suspend(struct device *dev)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct drm_device *drm_dev = pci_get_drvdata(pdev);
	int error;

	if (!drm_dev || !drm_dev->dev_private) {
		dev_err(dev, "DRM not initialized, aborting suspend.\n");
		return -ENODEV;
	}

	if (drm_dev->switch_power_state == DRM_SWITCH_POWER_OFF)
		return 0;

	error = i915_drm_freeze(drm_dev);
	if (error)
		return error;

	pci_disable_device(pdev);
	pci_set_power_state(pdev, PCI_D3hot);

	return 0;
}

static int i915_pm_resume(struct device *dev)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct drm_device *drm_dev = pci_get_drvdata(pdev);

	return i915_resume(drm_dev);
}

static int i915_pm_freeze(struct device *dev)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct drm_device *drm_dev = pci_get_drvdata(pdev);

	if (!drm_dev || !drm_dev->dev_private) {
		dev_err(dev, "DRM not initialized, aborting suspend.\n");
		return -ENODEV;
	}

	return i915_drm_freeze(drm_dev);
}

static int i915_pm_thaw(struct device *dev)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct drm_device *drm_dev = pci_get_drvdata(pdev);

	return i915_drm_thaw(drm_dev);
}

static int i915_pm_poweroff(struct device *dev)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct drm_device *drm_dev = pci_get_drvdata(pdev);

	return i915_drm_freeze(drm_dev);
}

static const struct dev_pm_ops i915_pm_ops = {
	.suspend = i915_pm_suspend,
	.resume = i915_pm_resume,
	.freeze = i915_pm_freeze,
	.thaw = i915_pm_thaw,
	.poweroff = i915_pm_poweroff,
	.restore = i915_pm_resume,
};

static struct vm_operations_struct i915_gem_vm_ops = {
	.fault = i915_gem_fault,
	.open = drm_gem_vm_open,
	.close = drm_gem_vm_close,
};

static struct drm_driver driver = {
	/* Don't use MTRRs here; the Xserver or userspace app should
	 * deal with them for Intel hardware.
	 */
	.driver_features =
	    DRIVER_USE_AGP | DRIVER_REQUIRE_AGP | /* DRIVER_USE_MTRR |*/
	    DRIVER_HAVE_IRQ | DRIVER_IRQ_SHARED | DRIVER_GEM,
	.load = i915_driver_load,
	.unload = i915_driver_unload,
	.open = i915_driver_open,
	.lastclose = i915_driver_lastclose,
	.preclose = i915_driver_preclose,
	.postclose = i915_driver_postclose,

	/* Used in place of i915_pm_ops for non-DRIVER_MODESET */
	.suspend = i915_suspend,
	.resume = i915_resume,

	.device_is_agp = i915_driver_device_is_agp,
	.reclaim_buffers = drm_core_reclaim_buffers,
	.master_create = i915_master_create,
	.master_destroy = i915_master_destroy,
#if defined(CONFIG_DEBUG_FS)
	.debugfs_init = i915_debugfs_init,
	.debugfs_cleanup = i915_debugfs_cleanup,
#endif
	.gem_init_object = i915_gem_init_object,
	.gem_free_object = i915_gem_free_object,
	.gem_vm_ops = &i915_gem_vm_ops,
	.dumb_create = i915_gem_dumb_create,
	.dumb_map_offset = i915_gem_mmap_gtt,
	.dumb_destroy = i915_gem_dumb_destroy,
	.ioctls = i915_ioctls,
	.fops = {
		 .owner = THIS_MODULE,
		 .open = drm_open,
		 .release = drm_release,
		 .unlocked_ioctl = drm_ioctl,
		 .mmap = drm_gem_mmap,
		 .poll = drm_poll,
		 .fasync = drm_fasync,
		 .read = drm_read,
#ifdef CONFIG_COMPAT
		 .compat_ioctl = i915_compat_ioctl,
#endif
		 .llseek = noop_llseek,
	},

	.name = DRIVER_NAME,
	.desc = DRIVER_DESC,
	.date = DRIVER_DATE,
	.major = DRIVER_MAJOR,
	.minor = DRIVER_MINOR,
	.patchlevel = DRIVER_PATCHLEVEL,
};

static struct pci_driver i915_pci_driver = {
	.name = DRIVER_NAME,
	.id_table = pciidlist,
	.probe = i915_pci_probe,
	.remove = i915_pci_remove,
	.driver.pm = &i915_pm_ops,
};

static int __init i915_init(void)
{
	if (!intel_agp_enabled) {
		DRM_ERROR("drm/i915 can't work without intel_agp module!\n");
		return -ENODEV;
	}

	driver.num_ioctls = i915_max_ioctl;

	/*
	 * If CONFIG_DRM_I915_KMS is set, default to KMS unless
	 * explicitly disabled with the module pararmeter.
	 *
	 * Otherwise, just follow the parameter (defaulting to off).
	 *
	 * Allow optional vga_text_mode_force boot option to override
	 * the default behavior.
	 */
#if defined(CONFIG_DRM_I915_KMS)
	if (i915_modeset != 0)
		driver.driver_features |= DRIVER_MODESET;
#endif
	if (i915_modeset == 1)
		driver.driver_features |= DRIVER_MODESET;

#ifdef CONFIG_VGA_CONSOLE
	if (vgacon_text_force() && i915_modeset == -1)
		driver.driver_features &= ~DRIVER_MODESET;
#endif

	if (!(driver.driver_features & DRIVER_MODESET))
		driver.get_vblank_timestamp = NULL;

	return drm_pci_init(&driver, &i915_pci_driver);
}

static void __exit i915_exit(void)
{
	drm_pci_exit(&driver, &i915_pci_driver);
}

module_init(i915_init);
module_exit(i915_exit);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL and additional rights");

/* We give fast paths for the really cool registers */
#define NEEDS_FORCE_WAKE(dev_priv, reg) \
	(((dev_priv)->info->gen >= 6) && \
	((reg) < 0x40000) && \
	((reg) != FORCEWAKE))

#define __i915_read(x, y) \
u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
	u##x val = 0; \
	if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
		gen6_gt_force_wake_get(dev_priv); \
		val = read##y(dev_priv->regs + reg); \
		gen6_gt_force_wake_put(dev_priv); \
	} else { \
		val = read##y(dev_priv->regs + reg); \
	} \
	trace_i915_reg_rw(false, reg, val, sizeof(val)); \
	return val; \
}

__i915_read(8, b)
__i915_read(16, w)
__i915_read(32, l)
__i915_read(64, q)
#undef __i915_read

#define __i915_write(x, y) \
void i915_write##x(struct drm_i915_private *dev_priv, u32 reg, u##x val) { \
	trace_i915_reg_rw(true, reg, val, sizeof(val)); \
	if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
		__gen6_gt_wait_for_fifo(dev_priv); \
	} \
	write##y(val, dev_priv->regs + reg); \
}
__i915_write(8, b)
__i915_write(16, w)
__i915_write(32, l)
__i915_write(64, q)
#undef __i915_write