drivers/gpu/drm/nouveau/nv04_dac.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright 2003 NVIDIA, Corporation
  * Copyright 2006 Dave Airlie
  * Copyright 2007 Maarten Maathuis
  * Copyright 2007-2009 Stuart Bennett
  *
  * 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, sublicense,
  * 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 NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS 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 "drmP.h"
 #include "drm_crtc_helper.h"

 #include "nouveau_drv.h"
 #include "nouveau_encoder.h"
 #include "nouveau_connector.h"
 #include "nouveau_crtc.h"
 #include "nouveau_hw.h"
 #include "nouveau_gpio.h"
 #include "nvreg.h"

 int nv04_dac_output_offset(struct drm_encoder *encoder)
 {
 	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;
 	int offset = 0;

 	if (dcb->or & (8 | OUTPUT_C))
 		offset += 0x68;
 	if (dcb->or & (8 | OUTPUT_B))
 		offset += 0x2000;

 	return offset;
 }

 /*
  * arbitrary limit to number of sense oscillations tolerated in one sample
  * period (observed to be at least 13 in "nvidia")
  */
 #define MAX_HBLANK_OSC 20

 /*
  * arbitrary limit to number of conflicting sample pairs to tolerate at a
  * voltage step (observed to be at least 5 in "nvidia")
  */
 #define MAX_SAMPLE_PAIRS 10

 static int sample_load_twice(struct drm_device *dev, bool sense[2])
 {
 	int i;

 	for (i = 0; i < 2; i++) {
 		bool sense_a, sense_b, sense_b_prime;
 		int j = 0;

 		/*
 		 * wait for bit 0 clear -- out of hblank -- (say reg value 0x4),
 		 * then wait for transition 0x4->0x5->0x4: enter hblank, leave
 		 * hblank again
 		 * use a 10ms timeout (guards against crtc being inactive, in
 		 * which case blank state would never change)
 		 */
 		if (!nouveau_wait_eq(dev, 10000000, NV_PRMCIO_INP0__COLOR,
 				     0x00000001, 0x00000000))
 			return -EBUSY;
 		if (!nouveau_wait_eq(dev, 10000000, NV_PRMCIO_INP0__COLOR,
 				     0x00000001, 0x00000001))
 			return -EBUSY;
 		if (!nouveau_wait_eq(dev, 10000000, NV_PRMCIO_INP0__COLOR,
 				     0x00000001, 0x00000000))
 			return -EBUSY;

 		udelay(100);
 		/* when level triggers, sense is _LO_ */
 		sense_a = nv_rd08(dev, NV_PRMCIO_INP0) & 0x10;

 		/* take another reading until it agrees with sense_a... */
 		do {
 			udelay(100);
 			sense_b = nv_rd08(dev, NV_PRMCIO_INP0) & 0x10;
 			if (sense_a != sense_b) {
 				sense_b_prime =
 					nv_rd08(dev, NV_PRMCIO_INP0) & 0x10;
 				if (sense_b == sense_b_prime) {
 					/* ... unless two consecutive subsequent
 					 * samples agree; sense_a is replaced */
 					sense_a = sense_b;
 					/* force mis-match so we loop */
 					sense_b = !sense_a;
 				}
 			}
 		} while ((sense_a != sense_b) && ++j < MAX_HBLANK_OSC);

 		if (j == MAX_HBLANK_OSC)
 			/* with so much oscillation, default to sense:LO */
 			sense[i] = false;
 		else
 			sense[i] = sense_a;
 	}

 	return 0;
 }

 static enum drm_connector_status nv04_dac_detect(struct drm_encoder *encoder,
 						 struct drm_connector *connector)
 {
 	struct drm_device *dev = encoder->dev;
 	uint8_t saved_seq1, saved_pi, saved_rpc1, saved_cr_mode;
 	uint8_t saved_palette0[3], saved_palette_mask;
 	uint32_t saved_rtest_ctrl, saved_rgen_ctrl;
 	int i;
 	uint8_t blue;
 	bool sense = true;

 	/*
 	 * for this detection to work, there needs to be a mode set up on the
 	 * CRTC.  this is presumed to be the case
 	 */

 	if (nv_two_heads(dev))
 		/* only implemented for head A for now */
 		NVSetOwner(dev, 0);

 	saved_cr_mode = NVReadVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX);
 	NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode | 0x80);

 	saved_seq1 = NVReadVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX);
 	NVWriteVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX, saved_seq1 & ~0x20);

 	saved_rtest_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL);
 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL,
 		      saved_rtest_ctrl & ~NV_PRAMDAC_TEST_CONTROL_PWRDWN_DAC_OFF);

 	msleep(10);

 	saved_pi = NVReadVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX);
 	NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX,
 		       saved_pi & ~(0x80 | MASK(NV_CIO_CRE_PIXEL_FORMAT)));
 	saved_rpc1 = NVReadVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX);
 	NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX, saved_rpc1 & ~0xc0);

 	nv_wr08(dev, NV_PRMDIO_READ_MODE_ADDRESS, 0x0);
 	for (i = 0; i < 3; i++)
 		saved_palette0[i] = nv_rd08(dev, NV_PRMDIO_PALETTE_DATA);
 	saved_palette_mask = nv_rd08(dev, NV_PRMDIO_PIXEL_MASK);
 	nv_wr08(dev, NV_PRMDIO_PIXEL_MASK, 0);

 	saved_rgen_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL);
 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL,
 		      (saved_rgen_ctrl & ~(NV_PRAMDAC_GENERAL_CONTROL_BPC_8BITS |
 					   NV_PRAMDAC_GENERAL_CONTROL_TERMINATION_75OHM)) |
 		      NV_PRAMDAC_GENERAL_CONTROL_PIXMIX_ON);

 	blue = 8;	/* start of test range */

 	do {
 		bool sense_pair[2];

 		nv_wr08(dev, NV_PRMDIO_WRITE_MODE_ADDRESS, 0);
 		nv_wr08(dev, NV_PRMDIO_PALETTE_DATA, 0);
 		nv_wr08(dev, NV_PRMDIO_PALETTE_DATA, 0);
 		/* testing blue won't find monochrome monitors.  I don't care */
 		nv_wr08(dev, NV_PRMDIO_PALETTE_DATA, blue);

 		i = 0;
 		/* take sample pairs until both samples in the pair agree */
 		do {
 			if (sample_load_twice(dev, sense_pair))
 				goto out;
 		} while ((sense_pair[0] != sense_pair[1]) &&
 							++i < MAX_SAMPLE_PAIRS);

 		if (i == MAX_SAMPLE_PAIRS)
 			/* too much oscillation defaults to LO */
 			sense = false;
 		else
 			sense = sense_pair[0];

 	/*
 	 * if sense goes LO before blue ramps to 0x18, monitor is not connected.
 	 * ergo, if blue gets to 0x18, monitor must be connected
 	 */
 	} while (++blue < 0x18 && sense);

 out:
 	nv_wr08(dev, NV_PRMDIO_PIXEL_MASK, saved_palette_mask);
 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL, saved_rgen_ctrl);
 	nv_wr08(dev, NV_PRMDIO_WRITE_MODE_ADDRESS, 0);
 	for (i = 0; i < 3; i++)
 		nv_wr08(dev, NV_PRMDIO_PALETTE_DATA, saved_palette0[i]);
 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL, saved_rtest_ctrl);
 	NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX, saved_pi);
 	NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX, saved_rpc1);
 	NVWriteVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX, saved_seq1);
 	NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode);

 	if (blue == 0x18) {
 		NV_INFO(dev, "Load detected on head A\n");
 		return connector_status_connected;
 	}

 	return connector_status_disconnected;
 }

 uint32_t nv17_dac_sample_load(struct drm_encoder *encoder)
 {
 	struct drm_device *dev = encoder->dev;
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
 	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;
 	uint32_t sample, testval, regoffset = nv04_dac_output_offset(encoder);
 	uint32_t saved_powerctrl_2 = 0, saved_powerctrl_4 = 0, saved_routput,
 		saved_rtest_ctrl, saved_gpio0, saved_gpio1, temp, routput;
 	int head;

 #define RGB_TEST_DATA(r, g, b) (r << 0 | g << 10 | b << 20)
 	if (dcb->type == OUTPUT_TV) {
 		testval = RGB_TEST_DATA(0xa0, 0xa0, 0xa0);

 		if (dev_priv->vbios.tvdactestval)
 			testval = dev_priv->vbios.tvdactestval;
 	} else {
 		testval = RGB_TEST_DATA(0x140, 0x140, 0x140); /* 0x94050140 */

 		if (dev_priv->vbios.dactestval)
 			testval = dev_priv->vbios.dactestval;
 	}

 	saved_rtest_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);
 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset,
 		      saved_rtest_ctrl & ~NV_PRAMDAC_TEST_CONTROL_PWRDWN_DAC_OFF);

 	saved_powerctrl_2 = nvReadMC(dev, NV_PBUS_POWERCTRL_2);

 	nvWriteMC(dev, NV_PBUS_POWERCTRL_2, saved_powerctrl_2 & 0xd7ffffff);
 	if (regoffset == 0x68) {
 		saved_powerctrl_4 = nvReadMC(dev, NV_PBUS_POWERCTRL_4);
 		nvWriteMC(dev, NV_PBUS_POWERCTRL_4, saved_powerctrl_4 & 0xffffffcf);
 	}

 	saved_gpio1 = nouveau_gpio_func_get(dev, DCB_GPIO_TVDAC1);
 	saved_gpio0 = nouveau_gpio_func_get(dev, DCB_GPIO_TVDAC0);

 	nouveau_gpio_func_set(dev, DCB_GPIO_TVDAC1, dcb->type == OUTPUT_TV);
 	nouveau_gpio_func_set(dev, DCB_GPIO_TVDAC0, dcb->type == OUTPUT_TV);

 	msleep(4);

 	saved_routput = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset);
 	head = (saved_routput & 0x100) >> 8;

 	/* if there's a spare crtc, using it will minimise flicker */
 	if (!(NVReadVgaCrtc(dev, head, NV_CIO_CRE_RPC1_INDEX) & 0xC0))
 		head ^= 1;

 	/* nv driver and nv31 use 0xfffffeee, nv34 and 6600 use 0xfffffece */
 	routput = (saved_routput & 0xfffffece) | head << 8;

 	if (dev_priv->card_type >= NV_40) {
 		if (dcb->type == OUTPUT_TV)
 			routput |= 0x1a << 16;
 		else
 			routput &= ~(0x1a << 16);
 	}

 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, routput);
 	msleep(1);

 	temp = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset);
 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, temp | 1);

 	NVWriteRAMDAC(dev, head, NV_PRAMDAC_TESTPOINT_DATA,
 		      NV_PRAMDAC_TESTPOINT_DATA_NOTBLANK | testval);
 	temp = NVReadRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL);
 	NVWriteRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL,
 		      temp | NV_PRAMDAC_TEST_CONTROL_TP_INS_EN_ASSERTED);
 	msleep(5);

 	sample = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);
 	/* do it again just in case it's a residual current */
 	sample &= NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);

 	temp = NVReadRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL);
 	NVWriteRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL,
 		      temp & ~NV_PRAMDAC_TEST_CONTROL_TP_INS_EN_ASSERTED);
 	NVWriteRAMDAC(dev, head, NV_PRAMDAC_TESTPOINT_DATA, 0);

 	/* bios does something more complex for restoring, but I think this is good enough */
 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, saved_routput);
 	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset, saved_rtest_ctrl);
 	if (regoffset == 0x68)
 		nvWriteMC(dev, NV_PBUS_POWERCTRL_4, saved_powerctrl_4);
 	nvWriteMC(dev, NV_PBUS_POWERCTRL_2, saved_powerctrl_2);

 	nouveau_gpio_func_set(dev, DCB_GPIO_TVDAC1, saved_gpio1);
 	nouveau_gpio_func_set(dev, DCB_GPIO_TVDAC0, saved_gpio0);

 	return sample;
 }

 static enum drm_connector_status
 nv17_dac_detect(struct drm_encoder *encoder, struct drm_connector *connector)
 {
 	struct drm_device *dev = encoder->dev;
 	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;

 	if (nv04_dac_in_use(encoder))
 		return connector_status_disconnected;

 	if (nv17_dac_sample_load(encoder) &
 	    NV_PRAMDAC_TEST_CONTROL_SENSEB_ALLHI) {
 		NV_INFO(dev, "Load detected on output %c\n",
 			'@' + ffs(dcb->or));
 		return connector_status_connected;
 	} else {
 		return connector_status_disconnected;
 	}
 }

 static bool nv04_dac_mode_fixup(struct drm_encoder *encoder,
 				struct drm_display_mode *mode,
 				struct drm_display_mode *adjusted_mode)
 {
 	if (nv04_dac_in_use(encoder))
 		return false;

 	return true;
 }

 static void nv04_dac_prepare(struct drm_encoder *encoder)
 {
 	struct drm_encoder_helper_funcs *helper = encoder->helper_private;
 	struct drm_device *dev = encoder->dev;
 	int head = nouveau_crtc(encoder->crtc)->index;

 	helper->dpms(encoder, DRM_MODE_DPMS_OFF);

 	nv04_dfp_disable(dev, head);
 }

 static void nv04_dac_mode_set(struct drm_encoder *encoder,
 			      struct drm_display_mode *mode,
 			      struct drm_display_mode *adjusted_mode)
 {
 	struct drm_device *dev = encoder->dev;
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
 	int head = nouveau_crtc(encoder->crtc)->index;

 	if (nv_gf4_disp_arch(dev)) {
 		struct drm_encoder *rebind;
 		uint32_t dac_offset = nv04_dac_output_offset(encoder);
 		uint32_t otherdac;

 		/* bit 16-19 are bits that are set on some G70 cards,
 		 * but don't seem to have much effect */
 		NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset,
 			      head << 8 | NV_PRAMDAC_DACCLK_SEL_DACCLK);
 		/* force any other vga encoders to bind to the other crtc */
 		list_for_each_entry(rebind, &dev->mode_config.encoder_list, head) {
 			if (rebind == encoder
 			    || nouveau_encoder(rebind)->dcb->type != OUTPUT_ANALOG)
 				continue;

 			dac_offset = nv04_dac_output_offset(rebind);
 			otherdac = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset);
 			NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset,
 				      (otherdac & ~0x0100) | (head ^ 1) << 8);
 		}
 	}

 	/* This could use refinement for flatpanels, but it should work this way */
 	if (dev_priv->chipset < 0x44)
 		NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + nv04_dac_output_offset(encoder), 0xf0000000);
 	else
 		NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + nv04_dac_output_offset(encoder), 0x00100000);
 }

 static void nv04_dac_commit(struct drm_encoder *encoder)
 {
 	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
 	struct drm_device *dev = encoder->dev;
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(encoder->crtc);
 	struct drm_encoder_helper_funcs *helper = encoder->helper_private;

 	helper->dpms(encoder, DRM_MODE_DPMS_ON);

 	NV_INFO(dev, "Output %s is running on CRTC %d using output %c\n",
 		drm_get_connector_name(&nouveau_encoder_connector_get(nv_encoder)->base),
 		nv_crtc->index, '@' + ffs(nv_encoder->dcb->or));
 }

 void nv04_dac_update_dacclk(struct drm_encoder *encoder, bool enable)
 {
 	struct drm_device *dev = encoder->dev;
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
 	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;

 	if (nv_gf4_disp_arch(dev)) {
 		uint32_t *dac_users = &dev_priv->dac_users[ffs(dcb->or) - 1];
 		int dacclk_off = NV_PRAMDAC_DACCLK + nv04_dac_output_offset(encoder);
 		uint32_t dacclk = NVReadRAMDAC(dev, 0, dacclk_off);

 		if (enable) {
 			*dac_users |= 1 << dcb->index;
 			NVWriteRAMDAC(dev, 0, dacclk_off, dacclk | NV_PRAMDAC_DACCLK_SEL_DACCLK);

 		} else {
 			*dac_users &= ~(1 << dcb->index);
 			if (!*dac_users)
 				NVWriteRAMDAC(dev, 0, dacclk_off,
 					dacclk & ~NV_PRAMDAC_DACCLK_SEL_DACCLK);
 		}
 	}
 }

 /* Check if the DAC corresponding to 'encoder' is being used by
  * someone else. */
 bool nv04_dac_in_use(struct drm_encoder *encoder)
 {
 	struct drm_nouveau_private *dev_priv = encoder->dev->dev_private;
 	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;

 	return nv_gf4_disp_arch(encoder->dev) &&
 		(dev_priv->dac_users[ffs(dcb->or) - 1] & ~(1 << dcb->index));
 }

 static void nv04_dac_dpms(struct drm_encoder *encoder, int mode)
 {
 	struct drm_device *dev = encoder->dev;
 	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);

 	if (nv_encoder->last_dpms == mode)
 		return;
 	nv_encoder->last_dpms = mode;

 	NV_INFO(dev, "Setting dpms mode %d on vga encoder (output %d)\n",
 		     mode, nv_encoder->dcb->index);

 	nv04_dac_update_dacclk(encoder, mode == DRM_MODE_DPMS_ON);
 }

 static void nv04_dac_save(struct drm_encoder *encoder)
 {
 	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
 	struct drm_device *dev = encoder->dev;

 	if (nv_gf4_disp_arch(dev))
 		nv_encoder->restore.output = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK +
 							  nv04_dac_output_offset(encoder));
 }

 static void nv04_dac_restore(struct drm_encoder *encoder)
 {
 	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
 	struct drm_device *dev = encoder->dev;

 	if (nv_gf4_disp_arch(dev))
 		NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + nv04_dac_output_offset(encoder),
 			      nv_encoder->restore.output);

 	nv_encoder->last_dpms = NV_DPMS_CLEARED;
 }

 static void nv04_dac_destroy(struct drm_encoder *encoder)
 {
 	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);

 	NV_DEBUG_KMS(encoder->dev, "\n");

 	drm_encoder_cleanup(encoder);
 	kfree(nv_encoder);
 }

 static const struct drm_encoder_helper_funcs nv04_dac_helper_funcs = {
 	.dpms = nv04_dac_dpms,
 	.save = nv04_dac_save,
 	.restore = nv04_dac_restore,
 	.mode_fixup = nv04_dac_mode_fixup,
 	.prepare = nv04_dac_prepare,
 	.commit = nv04_dac_commit,
 	.mode_set = nv04_dac_mode_set,
 	.detect = nv04_dac_detect
 };

 static const struct drm_encoder_helper_funcs nv17_dac_helper_funcs = {
 	.dpms = nv04_dac_dpms,
 	.save = nv04_dac_save,
 	.restore = nv04_dac_restore,
 	.mode_fixup = nv04_dac_mode_fixup,
 	.prepare = nv04_dac_prepare,
 	.commit = nv04_dac_commit,
 	.mode_set = nv04_dac_mode_set,
 	.detect = nv17_dac_detect
 };

 static const struct drm_encoder_funcs nv04_dac_funcs = {
 	.destroy = nv04_dac_destroy,
 };

 int
 nv04_dac_create(struct drm_connector *connector, struct dcb_entry *entry)
 {
 	const struct drm_encoder_helper_funcs *helper;
 	struct nouveau_encoder *nv_encoder = NULL;
 	struct drm_device *dev = connector->dev;
 	struct drm_encoder *encoder;

 	nv_encoder = kzalloc(sizeof(*nv_encoder), GFP_KERNEL);
 	if (!nv_encoder)
 		return -ENOMEM;

 	encoder = to_drm_encoder(nv_encoder);

 	nv_encoder->dcb = entry;
 	nv_encoder->or = ffs(entry->or) - 1;

 	if (nv_gf4_disp_arch(dev))
 		helper = &nv17_dac_helper_funcs;
 	else
 		helper = &nv04_dac_helper_funcs;

 	drm_encoder_init(dev, encoder, &nv04_dac_funcs, DRM_MODE_ENCODER_DAC);
 	drm_encoder_helper_add(encoder, helper);

 	encoder->possible_crtcs = entry->heads;
 	encoder->possible_clones = 0;

 	drm_mode_connector_attach_encoder(connector, encoder);
 	return 0;
 }
	/*
	* Copyright 2003 NVIDIA, Corporation
	* Copyright 2006 Dave Airlie
	* Copyright 2007 Maarten Maathuis
	* Copyright 2007-2009 Stuart Bennett
	*
	* 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, sublicense,
	* 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 NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS 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 "drmP.h"
	#include "drm_crtc_helper.h"

	#include "nouveau_drv.h"
	#include "nouveau_encoder.h"
	#include "nouveau_connector.h"
	#include "nouveau_crtc.h"
	#include "nouveau_hw.h"
	#include "nouveau_gpio.h"
	#include "nvreg.h"

	int nv04_dac_output_offset(struct drm_encoder *encoder)
	{
	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;
	int offset = 0;

	if (dcb->or & (8 \| OUTPUT_C))
	offset += 0x68;
	if (dcb->or & (8 \| OUTPUT_B))
	offset += 0x2000;

	return offset;
	}

	/*
	* arbitrary limit to number of sense oscillations tolerated in one sample
	* period (observed to be at least 13 in "nvidia")
	*/
	#define MAX_HBLANK_OSC 20

	/*
	* arbitrary limit to number of conflicting sample pairs to tolerate at a
	* voltage step (observed to be at least 5 in "nvidia")
	*/
	#define MAX_SAMPLE_PAIRS 10

	static int sample_load_twice(struct drm_device *dev, bool sense[2])
	{
	int i;

	for (i = 0; i < 2; i++) {
	bool sense_a, sense_b, sense_b_prime;
	int j = 0;

	/*
	* wait for bit 0 clear -- out of hblank -- (say reg value 0x4),
	* then wait for transition 0x4->0x5->0x4: enter hblank, leave
	* hblank again
	* use a 10ms timeout (guards against crtc being inactive, in
	* which case blank state would never change)
	*/
	if (!nouveau_wait_eq(dev, 10000000, NV_PRMCIO_INP0__COLOR,
	0x00000001, 0x00000000))
	return -EBUSY;
	if (!nouveau_wait_eq(dev, 10000000, NV_PRMCIO_INP0__COLOR,
	0x00000001, 0x00000001))
	return -EBUSY;
	if (!nouveau_wait_eq(dev, 10000000, NV_PRMCIO_INP0__COLOR,
	0x00000001, 0x00000000))
	return -EBUSY;

	udelay(100);
	/* when level triggers, sense is _LO_ */
	sense_a = nv_rd08(dev, NV_PRMCIO_INP0) & 0x10;

	/* take another reading until it agrees with sense_a... */
	do {
	udelay(100);
	sense_b = nv_rd08(dev, NV_PRMCIO_INP0) & 0x10;
	if (sense_a != sense_b) {
	sense_b_prime =
	nv_rd08(dev, NV_PRMCIO_INP0) & 0x10;
	if (sense_b == sense_b_prime) {
	/* ... unless two consecutive subsequent
	* samples agree; sense_a is replaced */
	sense_a = sense_b;
	/* force mis-match so we loop */
	sense_b = !sense_a;
	}
	}
	} while ((sense_a != sense_b) && ++j < MAX_HBLANK_OSC);

	if (j == MAX_HBLANK_OSC)
	/* with so much oscillation, default to sense:LO */
	sense[i] = false;
	else
	sense[i] = sense_a;
	}

	return 0;
	}

	static enum drm_connector_status nv04_dac_detect(struct drm_encoder *encoder,
	struct drm_connector *connector)
	{
	struct drm_device *dev = encoder->dev;
	uint8_t saved_seq1, saved_pi, saved_rpc1, saved_cr_mode;
	uint8_t saved_palette0[3], saved_palette_mask;
	uint32_t saved_rtest_ctrl, saved_rgen_ctrl;
	int i;
	uint8_t blue;
	bool sense = true;

	/*
	* for this detection to work, there needs to be a mode set up on the
	* CRTC. this is presumed to be the case
	*/

	if (nv_two_heads(dev))
	/* only implemented for head A for now */
	NVSetOwner(dev, 0);

	saved_cr_mode = NVReadVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX);
	NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode \| 0x80);

	saved_seq1 = NVReadVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX);
	NVWriteVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX, saved_seq1 & ~0x20);

	saved_rtest_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL);
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL,
	saved_rtest_ctrl & ~NV_PRAMDAC_TEST_CONTROL_PWRDWN_DAC_OFF);

	msleep(10);

	saved_pi = NVReadVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX);
	NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX,
	saved_pi & ~(0x80 \| MASK(NV_CIO_CRE_PIXEL_FORMAT)));
	saved_rpc1 = NVReadVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX);
	NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX, saved_rpc1 & ~0xc0);

	nv_wr08(dev, NV_PRMDIO_READ_MODE_ADDRESS, 0x0);
	for (i = 0; i < 3; i++)
	saved_palette0[i] = nv_rd08(dev, NV_PRMDIO_PALETTE_DATA);
	saved_palette_mask = nv_rd08(dev, NV_PRMDIO_PIXEL_MASK);
	nv_wr08(dev, NV_PRMDIO_PIXEL_MASK, 0);

	saved_rgen_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL);
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL,
	(saved_rgen_ctrl & ~(NV_PRAMDAC_GENERAL_CONTROL_BPC_8BITS \|
	NV_PRAMDAC_GENERAL_CONTROL_TERMINATION_75OHM)) \|
	NV_PRAMDAC_GENERAL_CONTROL_PIXMIX_ON);

	blue = 8; /* start of test range */

	do {
	bool sense_pair[2];

	nv_wr08(dev, NV_PRMDIO_WRITE_MODE_ADDRESS, 0);
	nv_wr08(dev, NV_PRMDIO_PALETTE_DATA, 0);
	nv_wr08(dev, NV_PRMDIO_PALETTE_DATA, 0);
	/* testing blue won't find monochrome monitors. I don't care */
	nv_wr08(dev, NV_PRMDIO_PALETTE_DATA, blue);

	i = 0;
	/* take sample pairs until both samples in the pair agree */
	do {
	if (sample_load_twice(dev, sense_pair))
	goto out;
	} while ((sense_pair[0] != sense_pair[1]) &&
	++i < MAX_SAMPLE_PAIRS);

	if (i == MAX_SAMPLE_PAIRS)
	/* too much oscillation defaults to LO */
	sense = false;
	else
	sense = sense_pair[0];

	/*
	* if sense goes LO before blue ramps to 0x18, monitor is not connected.
	* ergo, if blue gets to 0x18, monitor must be connected
	*/
	} while (++blue < 0x18 && sense);

	out:
	nv_wr08(dev, NV_PRMDIO_PIXEL_MASK, saved_palette_mask);
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_GENERAL_CONTROL, saved_rgen_ctrl);
	nv_wr08(dev, NV_PRMDIO_WRITE_MODE_ADDRESS, 0);
	for (i = 0; i < 3; i++)
	nv_wr08(dev, NV_PRMDIO_PALETTE_DATA, saved_palette0[i]);
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL, saved_rtest_ctrl);
	NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX, saved_pi);
	NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX, saved_rpc1);
	NVWriteVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX, saved_seq1);
	NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode);

	if (blue == 0x18) {
	NV_INFO(dev, "Load detected on head A\n");
	return connector_status_connected;
	}

	return connector_status_disconnected;
	}

	uint32_t nv17_dac_sample_load(struct drm_encoder *encoder)
	{
	struct drm_device *dev = encoder->dev;
	struct drm_nouveau_private *dev_priv = dev->dev_private;
	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;
	uint32_t sample, testval, regoffset = nv04_dac_output_offset(encoder);
	uint32_t saved_powerctrl_2 = 0, saved_powerctrl_4 = 0, saved_routput,
	saved_rtest_ctrl, saved_gpio0, saved_gpio1, temp, routput;
	int head;

	#define RGB_TEST_DATA(r, g, b) (r << 0 \| g << 10 \| b << 20)
	if (dcb->type == OUTPUT_TV) {
	testval = RGB_TEST_DATA(0xa0, 0xa0, 0xa0);

	if (dev_priv->vbios.tvdactestval)
	testval = dev_priv->vbios.tvdactestval;
	} else {
	testval = RGB_TEST_DATA(0x140, 0x140, 0x140); /* 0x94050140 */

	if (dev_priv->vbios.dactestval)
	testval = dev_priv->vbios.dactestval;
	}

	saved_rtest_ctrl = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset,
	saved_rtest_ctrl & ~NV_PRAMDAC_TEST_CONTROL_PWRDWN_DAC_OFF);

	saved_powerctrl_2 = nvReadMC(dev, NV_PBUS_POWERCTRL_2);

	nvWriteMC(dev, NV_PBUS_POWERCTRL_2, saved_powerctrl_2 & 0xd7ffffff);
	if (regoffset == 0x68) {
	saved_powerctrl_4 = nvReadMC(dev, NV_PBUS_POWERCTRL_4);
	nvWriteMC(dev, NV_PBUS_POWERCTRL_4, saved_powerctrl_4 & 0xffffffcf);
	}

	saved_gpio1 = nouveau_gpio_func_get(dev, DCB_GPIO_TVDAC1);
	saved_gpio0 = nouveau_gpio_func_get(dev, DCB_GPIO_TVDAC0);

	nouveau_gpio_func_set(dev, DCB_GPIO_TVDAC1, dcb->type == OUTPUT_TV);
	nouveau_gpio_func_set(dev, DCB_GPIO_TVDAC0, dcb->type == OUTPUT_TV);

	msleep(4);

	saved_routput = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset);
	head = (saved_routput & 0x100) >> 8;

	/* if there's a spare crtc, using it will minimise flicker */
	if (!(NVReadVgaCrtc(dev, head, NV_CIO_CRE_RPC1_INDEX) & 0xC0))
	head ^= 1;

	/* nv driver and nv31 use 0xfffffeee, nv34 and 6600 use 0xfffffece */
	routput = (saved_routput & 0xfffffece) \| head << 8;

	if (dev_priv->card_type >= NV_40) {
	if (dcb->type == OUTPUT_TV)
	routput \|= 0x1a << 16;
	else
	routput &= ~(0x1a << 16);
	}

	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, routput);
	msleep(1);

	temp = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset);
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, temp \| 1);

	NVWriteRAMDAC(dev, head, NV_PRAMDAC_TESTPOINT_DATA,
	NV_PRAMDAC_TESTPOINT_DATA_NOTBLANK \| testval);
	temp = NVReadRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL);
	NVWriteRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL,
	temp \| NV_PRAMDAC_TEST_CONTROL_TP_INS_EN_ASSERTED);
	msleep(5);

	sample = NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);
	/* do it again just in case it's a residual current */
	sample &= NVReadRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset);

	temp = NVReadRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL);
	NVWriteRAMDAC(dev, head, NV_PRAMDAC_TEST_CONTROL,
	temp & ~NV_PRAMDAC_TEST_CONTROL_TP_INS_EN_ASSERTED);
	NVWriteRAMDAC(dev, head, NV_PRAMDAC_TESTPOINT_DATA, 0);

	/* bios does something more complex for restoring, but I think this is good enough */
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + regoffset, saved_routput);
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + regoffset, saved_rtest_ctrl);
	if (regoffset == 0x68)
	nvWriteMC(dev, NV_PBUS_POWERCTRL_4, saved_powerctrl_4);
	nvWriteMC(dev, NV_PBUS_POWERCTRL_2, saved_powerctrl_2);

	nouveau_gpio_func_set(dev, DCB_GPIO_TVDAC1, saved_gpio1);
	nouveau_gpio_func_set(dev, DCB_GPIO_TVDAC0, saved_gpio0);

	return sample;
	}

	static enum drm_connector_status
	nv17_dac_detect(struct drm_encoder encoder, struct drm_connector connector)
	{
	struct drm_device *dev = encoder->dev;
	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;

	if (nv04_dac_in_use(encoder))
	return connector_status_disconnected;

	if (nv17_dac_sample_load(encoder) &
	NV_PRAMDAC_TEST_CONTROL_SENSEB_ALLHI) {
	NV_INFO(dev, "Load detected on output %c\n",
	'@' + ffs(dcb->or));
	return connector_status_connected;
	} else {
	return connector_status_disconnected;
	}
	}

	static bool nv04_dac_mode_fixup(struct drm_encoder *encoder,
	struct drm_display_mode *mode,
	struct drm_display_mode *adjusted_mode)
	{
	if (nv04_dac_in_use(encoder))
	return false;

	return true;
	}

	static void nv04_dac_prepare(struct drm_encoder *encoder)
	{
	struct drm_encoder_helper_funcs *helper = encoder->helper_private;
	struct drm_device *dev = encoder->dev;
	int head = nouveau_crtc(encoder->crtc)->index;

	helper->dpms(encoder, DRM_MODE_DPMS_OFF);

	nv04_dfp_disable(dev, head);
	}

	static void nv04_dac_mode_set(struct drm_encoder *encoder,
	struct drm_display_mode *mode,
	struct drm_display_mode *adjusted_mode)
	{
	struct drm_device *dev = encoder->dev;
	struct drm_nouveau_private *dev_priv = dev->dev_private;
	int head = nouveau_crtc(encoder->crtc)->index;

	if (nv_gf4_disp_arch(dev)) {
	struct drm_encoder *rebind;
	uint32_t dac_offset = nv04_dac_output_offset(encoder);
	uint32_t otherdac;

	/* bit 16-19 are bits that are set on some G70 cards,
	* but don't seem to have much effect */
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset,
	head << 8 \| NV_PRAMDAC_DACCLK_SEL_DACCLK);
	/* force any other vga encoders to bind to the other crtc */
	list_for_each_entry(rebind, &dev->mode_config.encoder_list, head) {
	if (rebind == encoder
	\|\| nouveau_encoder(rebind)->dcb->type != OUTPUT_ANALOG)
	continue;

	dac_offset = nv04_dac_output_offset(rebind);
	otherdac = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset);
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + dac_offset,
	(otherdac & ~0x0100) \| (head ^ 1) << 8);
	}
	}

	/* This could use refinement for flatpanels, but it should work this way */
	if (dev_priv->chipset < 0x44)
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + nv04_dac_output_offset(encoder), 0xf0000000);
	else
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_TEST_CONTROL + nv04_dac_output_offset(encoder), 0x00100000);
	}

	static void nv04_dac_commit(struct drm_encoder *encoder)
	{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct drm_device *dev = encoder->dev;
	struct nouveau_crtc *nv_crtc = nouveau_crtc(encoder->crtc);
	struct drm_encoder_helper_funcs *helper = encoder->helper_private;

	helper->dpms(encoder, DRM_MODE_DPMS_ON);

	NV_INFO(dev, "Output %s is running on CRTC %d using output %c\n",
	drm_get_connector_name(&nouveau_encoder_connector_get(nv_encoder)->base),
	nv_crtc->index, '@' + ffs(nv_encoder->dcb->or));
	}

	void nv04_dac_update_dacclk(struct drm_encoder *encoder, bool enable)
	{
	struct drm_device *dev = encoder->dev;
	struct drm_nouveau_private *dev_priv = dev->dev_private;
	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;

	if (nv_gf4_disp_arch(dev)) {
	uint32_t *dac_users = &dev_priv->dac_users[ffs(dcb->or) - 1];
	int dacclk_off = NV_PRAMDAC_DACCLK + nv04_dac_output_offset(encoder);
	uint32_t dacclk = NVReadRAMDAC(dev, 0, dacclk_off);

	if (enable) {
	*dac_users \|= 1 << dcb->index;
	NVWriteRAMDAC(dev, 0, dacclk_off, dacclk \| NV_PRAMDAC_DACCLK_SEL_DACCLK);

	} else {
	*dac_users &= ~(1 << dcb->index);
	if (!*dac_users)
	NVWriteRAMDAC(dev, 0, dacclk_off,
	dacclk & ~NV_PRAMDAC_DACCLK_SEL_DACCLK);
	}
	}
	}

	/* Check if the DAC corresponding to 'encoder' is being used by
	* someone else. */
	bool nv04_dac_in_use(struct drm_encoder *encoder)
	{
	struct drm_nouveau_private *dev_priv = encoder->dev->dev_private;
	struct dcb_entry *dcb = nouveau_encoder(encoder)->dcb;

	return nv_gf4_disp_arch(encoder->dev) &&
	(dev_priv->dac_users[ffs(dcb->or) - 1] & ~(1 << dcb->index));
	}

	static void nv04_dac_dpms(struct drm_encoder *encoder, int mode)
	{
	struct drm_device *dev = encoder->dev;
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);

	if (nv_encoder->last_dpms == mode)
	return;
	nv_encoder->last_dpms = mode;

	NV_INFO(dev, "Setting dpms mode %d on vga encoder (output %d)\n",
	mode, nv_encoder->dcb->index);

	nv04_dac_update_dacclk(encoder, mode == DRM_MODE_DPMS_ON);
	}

	static void nv04_dac_save(struct drm_encoder *encoder)
	{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct drm_device *dev = encoder->dev;

	if (nv_gf4_disp_arch(dev))
	nv_encoder->restore.output = NVReadRAMDAC(dev, 0, NV_PRAMDAC_DACCLK +
	nv04_dac_output_offset(encoder));
	}

	static void nv04_dac_restore(struct drm_encoder *encoder)
	{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct drm_device *dev = encoder->dev;

	if (nv_gf4_disp_arch(dev))
	NVWriteRAMDAC(dev, 0, NV_PRAMDAC_DACCLK + nv04_dac_output_offset(encoder),
	nv_encoder->restore.output);

	nv_encoder->last_dpms = NV_DPMS_CLEARED;
	}

	static void nv04_dac_destroy(struct drm_encoder *encoder)
	{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);

	NV_DEBUG_KMS(encoder->dev, "\n");

	drm_encoder_cleanup(encoder);
	kfree(nv_encoder);
	}

	static const struct drm_encoder_helper_funcs nv04_dac_helper_funcs = {
	.dpms = nv04_dac_dpms,
	.save = nv04_dac_save,
	.restore = nv04_dac_restore,
	.mode_fixup = nv04_dac_mode_fixup,
	.prepare = nv04_dac_prepare,
	.commit = nv04_dac_commit,
	.mode_set = nv04_dac_mode_set,
	.detect = nv04_dac_detect
	};

	static const struct drm_encoder_helper_funcs nv17_dac_helper_funcs = {
	.dpms = nv04_dac_dpms,
	.save = nv04_dac_save,
	.restore = nv04_dac_restore,
	.mode_fixup = nv04_dac_mode_fixup,
	.prepare = nv04_dac_prepare,
	.commit = nv04_dac_commit,
	.mode_set = nv04_dac_mode_set,
	.detect = nv17_dac_detect
	};

	static const struct drm_encoder_funcs nv04_dac_funcs = {
	.destroy = nv04_dac_destroy,
	};

	int
	nv04_dac_create(struct drm_connector connector, struct dcb_entry entry)
	{
	const struct drm_encoder_helper_funcs *helper;
	struct nouveau_encoder *nv_encoder = NULL;
	struct drm_device *dev = connector->dev;
	struct drm_encoder *encoder;

	nv_encoder = kzalloc(sizeof(*nv_encoder), GFP_KERNEL);
	if (!nv_encoder)
	return -ENOMEM;

	encoder = to_drm_encoder(nv_encoder);

	nv_encoder->dcb = entry;
	nv_encoder->or = ffs(entry->or) - 1;

	if (nv_gf4_disp_arch(dev))
	helper = &nv17_dac_helper_funcs;
	else
	helper = &nv04_dac_helper_funcs;

	drm_encoder_init(dev, encoder, &nv04_dac_funcs, DRM_MODE_ENCODER_DAC);
	drm_encoder_helper_add(encoder, helper);

	encoder->possible_crtcs = entry->heads;
	encoder->possible_clones = 0;

	drm_mode_connector_attach_encoder(connector, encoder);
	return 0;
	}