blob: 5fbb767fcd6327e727877d7bde2696b041c075f8 [file] [log] [blame]
// SPDX-License-Identifier: MIT
/*
* Copyright © 2020-2021 Intel Corporation
*/
#include "i915_drv.h"
#include "i915_trace.h"
#include "intel_display_types.h"
#include "intel_dp_aux.h"
#include "intel_pps.h"
#include "intel_tc.h"
u32 intel_dp_pack_aux(const u8 *src, int src_bytes)
{
int i;
u32 v = 0;
if (src_bytes > 4)
src_bytes = 4;
for (i = 0; i < src_bytes; i++)
v |= ((u32)src[i]) << ((3 - i) * 8);
return v;
}
static void intel_dp_unpack_aux(u32 src, u8 *dst, int dst_bytes)
{
int i;
if (dst_bytes > 4)
dst_bytes = 4;
for (i = 0; i < dst_bytes; i++)
dst[i] = src >> ((3 - i) * 8);
}
static u32
intel_dp_aux_wait_done(struct intel_dp *intel_dp)
{
struct drm_i915_private *i915 = dp_to_i915(intel_dp);
i915_reg_t ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
const unsigned int timeout_ms = 10;
u32 status;
bool done;
#define C (((status = intel_uncore_read_notrace(&i915->uncore, ch_ctl)) & DP_AUX_CH_CTL_SEND_BUSY) == 0)
done = wait_event_timeout(i915->gmbus_wait_queue, C,
msecs_to_jiffies_timeout(timeout_ms));
/* just trace the final value */
trace_i915_reg_rw(false, ch_ctl, status, sizeof(status), true);
if (!done)
drm_err(&i915->drm,
"%s: did not complete or timeout within %ums (status 0x%08x)\n",
intel_dp->aux.name, timeout_ms, status);
#undef C
return status;
}
static u32 g4x_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
if (index)
return 0;
/*
* The clock divider is based off the hrawclk, and would like to run at
* 2MHz. So, take the hrawclk value and divide by 2000 and use that
*/
return DIV_ROUND_CLOSEST(RUNTIME_INFO(dev_priv)->rawclk_freq, 2000);
}
static u32 ilk_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
u32 freq;
if (index)
return 0;
/*
* The clock divider is based off the cdclk or PCH rawclk, and would
* like to run at 2MHz. So, take the cdclk or PCH rawclk value and
* divide by 2000 and use that
*/
if (dig_port->aux_ch == AUX_CH_A)
freq = dev_priv->cdclk.hw.cdclk;
else
freq = RUNTIME_INFO(dev_priv)->rawclk_freq;
return DIV_ROUND_CLOSEST(freq, 2000);
}
static u32 hsw_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
if (dig_port->aux_ch != AUX_CH_A && HAS_PCH_LPT_H(dev_priv)) {
/* Workaround for non-ULT HSW */
switch (index) {
case 0: return 63;
case 1: return 72;
default: return 0;
}
}
return ilk_get_aux_clock_divider(intel_dp, index);
}
static u32 skl_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
{
/*
* SKL doesn't need us to program the AUX clock divider (Hardware will
* derive the clock from CDCLK automatically). We still implement the
* get_aux_clock_divider vfunc to plug-in into the existing code.
*/
return index ? 0 : 1;
}
static u32 g4x_get_aux_send_ctl(struct intel_dp *intel_dp,
int send_bytes,
u32 aux_clock_divider)
{
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
struct drm_i915_private *dev_priv =
to_i915(dig_port->base.base.dev);
u32 timeout;
/* Max timeout value on G4x-BDW: 1.6ms */
if (IS_BROADWELL(dev_priv))
timeout = DP_AUX_CH_CTL_TIME_OUT_600us;
else
timeout = DP_AUX_CH_CTL_TIME_OUT_400us;
return DP_AUX_CH_CTL_SEND_BUSY |
DP_AUX_CH_CTL_DONE |
DP_AUX_CH_CTL_INTERRUPT |
DP_AUX_CH_CTL_TIME_OUT_ERROR |
timeout |
DP_AUX_CH_CTL_RECEIVE_ERROR |
(send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
(3 << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
(aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT);
}
static u32 skl_get_aux_send_ctl(struct intel_dp *intel_dp,
int send_bytes,
u32 unused)
{
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
u32 ret;
/*
* Max timeout values:
* SKL-GLK: 1.6ms
* ICL+: 4ms
*/
ret = DP_AUX_CH_CTL_SEND_BUSY |
DP_AUX_CH_CTL_DONE |
DP_AUX_CH_CTL_INTERRUPT |
DP_AUX_CH_CTL_TIME_OUT_ERROR |
DP_AUX_CH_CTL_TIME_OUT_MAX |
DP_AUX_CH_CTL_RECEIVE_ERROR |
(send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(32) |
DP_AUX_CH_CTL_SYNC_PULSE_SKL(32);
if (intel_tc_port_in_tbt_alt_mode(dig_port))
ret |= DP_AUX_CH_CTL_TBT_IO;
return ret;
}
static int
intel_dp_aux_xfer(struct intel_dp *intel_dp,
const u8 *send, int send_bytes,
u8 *recv, int recv_size,
u32 aux_send_ctl_flags)
{
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
struct drm_i915_private *i915 =
to_i915(dig_port->base.base.dev);
struct intel_uncore *uncore = &i915->uncore;
enum phy phy = intel_port_to_phy(i915, dig_port->base.port);
bool is_tc_port = intel_phy_is_tc(i915, phy);
i915_reg_t ch_ctl, ch_data[5];
u32 aux_clock_divider;
enum intel_display_power_domain aux_domain;
intel_wakeref_t aux_wakeref;
intel_wakeref_t pps_wakeref;
int i, ret, recv_bytes;
int try, clock = 0;
u32 status;
bool vdd;
ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
for (i = 0; i < ARRAY_SIZE(ch_data); i++)
ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i);
if (is_tc_port)
intel_tc_port_lock(dig_port);
aux_domain = intel_aux_power_domain(dig_port);
aux_wakeref = intel_display_power_get(i915, aux_domain);
pps_wakeref = intel_pps_lock(intel_dp);
/*
* We will be called with VDD already enabled for dpcd/edid/oui reads.
* In such cases we want to leave VDD enabled and it's up to upper layers
* to turn it off. But for eg. i2c-dev access we need to turn it on/off
* ourselves.
*/
vdd = intel_pps_vdd_on_unlocked(intel_dp);
/*
* dp aux is extremely sensitive to irq latency, hence request the
* lowest possible wakeup latency and so prevent the cpu from going into
* deep sleep states.
*/
cpu_latency_qos_update_request(&intel_dp->pm_qos, 0);
intel_pps_check_power_unlocked(intel_dp);
/* Try to wait for any previous AUX channel activity */
for (try = 0; try < 3; try++) {
status = intel_uncore_read_notrace(uncore, ch_ctl);
if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
break;
msleep(1);
}
/* just trace the final value */
trace_i915_reg_rw(false, ch_ctl, status, sizeof(status), true);
if (try == 3) {
const u32 status = intel_uncore_read(uncore, ch_ctl);
if (status != intel_dp->aux_busy_last_status) {
drm_WARN(&i915->drm, 1,
"%s: not started (status 0x%08x)\n",
intel_dp->aux.name, status);
intel_dp->aux_busy_last_status = status;
}
ret = -EBUSY;
goto out;
}
/* Only 5 data registers! */
if (drm_WARN_ON(&i915->drm, send_bytes > 20 || recv_size > 20)) {
ret = -E2BIG;
goto out;
}
while ((aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, clock++))) {
u32 send_ctl = intel_dp->get_aux_send_ctl(intel_dp,
send_bytes,
aux_clock_divider);
send_ctl |= aux_send_ctl_flags;
/* Must try at least 3 times according to DP spec */
for (try = 0; try < 5; try++) {
/* Load the send data into the aux channel data registers */
for (i = 0; i < send_bytes; i += 4)
intel_uncore_write(uncore,
ch_data[i >> 2],
intel_dp_pack_aux(send + i,
send_bytes - i));
/* Send the command and wait for it to complete */
intel_uncore_write(uncore, ch_ctl, send_ctl);
status = intel_dp_aux_wait_done(intel_dp);
/* Clear done status and any errors */
intel_uncore_write(uncore,
ch_ctl,
status |
DP_AUX_CH_CTL_DONE |
DP_AUX_CH_CTL_TIME_OUT_ERROR |
DP_AUX_CH_CTL_RECEIVE_ERROR);
/*
* DP CTS 1.2 Core Rev 1.1, 4.2.1.1 & 4.2.1.2
* 400us delay required for errors and timeouts
* Timeout errors from the HW already meet this
* requirement so skip to next iteration
*/
if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR)
continue;
if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
usleep_range(400, 500);
continue;
}
if (status & DP_AUX_CH_CTL_DONE)
goto done;
}
}
if ((status & DP_AUX_CH_CTL_DONE) == 0) {
drm_err(&i915->drm, "%s: not done (status 0x%08x)\n",
intel_dp->aux.name, status);
ret = -EBUSY;
goto out;
}
done:
/*
* Check for timeout or receive error. Timeouts occur when the sink is
* not connected.
*/
if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
drm_err(&i915->drm, "%s: receive error (status 0x%08x)\n",
intel_dp->aux.name, status);
ret = -EIO;
goto out;
}
/*
* Timeouts occur when the device isn't connected, so they're "normal"
* -- don't fill the kernel log with these
*/
if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) {
drm_dbg_kms(&i915->drm, "%s: timeout (status 0x%08x)\n",
intel_dp->aux.name, status);
ret = -ETIMEDOUT;
goto out;
}
/* Unload any bytes sent back from the other side */
recv_bytes = ((status & DP_AUX_CH_CTL_MESSAGE_SIZE_MASK) >>
DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT);
/*
* By BSpec: "Message sizes of 0 or >20 are not allowed."
* We have no idea of what happened so we return -EBUSY so
* drm layer takes care for the necessary retries.
*/
if (recv_bytes == 0 || recv_bytes > 20) {
drm_dbg_kms(&i915->drm,
"%s: Forbidden recv_bytes = %d on aux transaction\n",
intel_dp->aux.name, recv_bytes);
ret = -EBUSY;
goto out;
}
if (recv_bytes > recv_size)
recv_bytes = recv_size;
for (i = 0; i < recv_bytes; i += 4)
intel_dp_unpack_aux(intel_uncore_read(uncore, ch_data[i >> 2]),
recv + i, recv_bytes - i);
ret = recv_bytes;
out:
cpu_latency_qos_update_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
if (vdd)
intel_pps_vdd_off_unlocked(intel_dp, false);
intel_pps_unlock(intel_dp, pps_wakeref);
intel_display_power_put_async(i915, aux_domain, aux_wakeref);
if (is_tc_port)
intel_tc_port_unlock(dig_port);
return ret;
}
#define BARE_ADDRESS_SIZE 3
#define HEADER_SIZE (BARE_ADDRESS_SIZE + 1)
static void
intel_dp_aux_header(u8 txbuf[HEADER_SIZE],
const struct drm_dp_aux_msg *msg)
{
txbuf[0] = (msg->request << 4) | ((msg->address >> 16) & 0xf);
txbuf[1] = (msg->address >> 8) & 0xff;
txbuf[2] = msg->address & 0xff;
txbuf[3] = msg->size - 1;
}
static u32 intel_dp_aux_xfer_flags(const struct drm_dp_aux_msg *msg)
{
/*
* If we're trying to send the HDCP Aksv, we need to set a the Aksv
* select bit to inform the hardware to send the Aksv after our header
* since we can't access that data from software.
*/
if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_WRITE &&
msg->address == DP_AUX_HDCP_AKSV)
return DP_AUX_CH_CTL_AUX_AKSV_SELECT;
return 0;
}
static ssize_t
intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
{
struct intel_dp *intel_dp = container_of(aux, struct intel_dp, aux);
struct drm_i915_private *i915 = dp_to_i915(intel_dp);
u8 txbuf[20], rxbuf[20];
size_t txsize, rxsize;
u32 flags = intel_dp_aux_xfer_flags(msg);
int ret;
intel_dp_aux_header(txbuf, msg);
switch (msg->request & ~DP_AUX_I2C_MOT) {
case DP_AUX_NATIVE_WRITE:
case DP_AUX_I2C_WRITE:
case DP_AUX_I2C_WRITE_STATUS_UPDATE:
txsize = msg->size ? HEADER_SIZE + msg->size : BARE_ADDRESS_SIZE;
rxsize = 2; /* 0 or 1 data bytes */
if (drm_WARN_ON(&i915->drm, txsize > 20))
return -E2BIG;
drm_WARN_ON(&i915->drm, !msg->buffer != !msg->size);
if (msg->buffer)
memcpy(txbuf + HEADER_SIZE, msg->buffer, msg->size);
ret = intel_dp_aux_xfer(intel_dp, txbuf, txsize,
rxbuf, rxsize, flags);
if (ret > 0) {
msg->reply = rxbuf[0] >> 4;
if (ret > 1) {
/* Number of bytes written in a short write. */
ret = clamp_t(int, rxbuf[1], 0, msg->size);
} else {
/* Return payload size. */
ret = msg->size;
}
}
break;
case DP_AUX_NATIVE_READ:
case DP_AUX_I2C_READ:
txsize = msg->size ? HEADER_SIZE : BARE_ADDRESS_SIZE;
rxsize = msg->size + 1;
if (drm_WARN_ON(&i915->drm, rxsize > 20))
return -E2BIG;
ret = intel_dp_aux_xfer(intel_dp, txbuf, txsize,
rxbuf, rxsize, flags);
if (ret > 0) {
msg->reply = rxbuf[0] >> 4;
/*
* Assume happy day, and copy the data. The caller is
* expected to check msg->reply before touching it.
*
* Return payload size.
*/
ret--;
memcpy(msg->buffer, rxbuf + 1, ret);
}
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static i915_reg_t g4x_aux_ctl_reg(struct intel_dp *intel_dp)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
enum aux_ch aux_ch = dig_port->aux_ch;
switch (aux_ch) {
case AUX_CH_B:
case AUX_CH_C:
case AUX_CH_D:
return DP_AUX_CH_CTL(aux_ch);
default:
MISSING_CASE(aux_ch);
return DP_AUX_CH_CTL(AUX_CH_B);
}
}
static i915_reg_t g4x_aux_data_reg(struct intel_dp *intel_dp, int index)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
enum aux_ch aux_ch = dig_port->aux_ch;
switch (aux_ch) {
case AUX_CH_B:
case AUX_CH_C:
case AUX_CH_D:
return DP_AUX_CH_DATA(aux_ch, index);
default:
MISSING_CASE(aux_ch);
return DP_AUX_CH_DATA(AUX_CH_B, index);
}
}
static i915_reg_t ilk_aux_ctl_reg(struct intel_dp *intel_dp)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
enum aux_ch aux_ch = dig_port->aux_ch;
switch (aux_ch) {
case AUX_CH_A:
return DP_AUX_CH_CTL(aux_ch);
case AUX_CH_B:
case AUX_CH_C:
case AUX_CH_D:
return PCH_DP_AUX_CH_CTL(aux_ch);
default:
MISSING_CASE(aux_ch);
return DP_AUX_CH_CTL(AUX_CH_A);
}
}
static i915_reg_t ilk_aux_data_reg(struct intel_dp *intel_dp, int index)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
enum aux_ch aux_ch = dig_port->aux_ch;
switch (aux_ch) {
case AUX_CH_A:
return DP_AUX_CH_DATA(aux_ch, index);
case AUX_CH_B:
case AUX_CH_C:
case AUX_CH_D:
return PCH_DP_AUX_CH_DATA(aux_ch, index);
default:
MISSING_CASE(aux_ch);
return DP_AUX_CH_DATA(AUX_CH_A, index);
}
}
static i915_reg_t skl_aux_ctl_reg(struct intel_dp *intel_dp)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
enum aux_ch aux_ch = dig_port->aux_ch;
switch (aux_ch) {
case AUX_CH_A:
case AUX_CH_B:
case AUX_CH_C:
case AUX_CH_D:
case AUX_CH_E:
case AUX_CH_F:
return DP_AUX_CH_CTL(aux_ch);
default:
MISSING_CASE(aux_ch);
return DP_AUX_CH_CTL(AUX_CH_A);
}
}
static i915_reg_t skl_aux_data_reg(struct intel_dp *intel_dp, int index)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
enum aux_ch aux_ch = dig_port->aux_ch;
switch (aux_ch) {
case AUX_CH_A:
case AUX_CH_B:
case AUX_CH_C:
case AUX_CH_D:
case AUX_CH_E:
case AUX_CH_F:
return DP_AUX_CH_DATA(aux_ch, index);
default:
MISSING_CASE(aux_ch);
return DP_AUX_CH_DATA(AUX_CH_A, index);
}
}
static i915_reg_t tgl_aux_ctl_reg(struct intel_dp *intel_dp)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
enum aux_ch aux_ch = dig_port->aux_ch;
switch (aux_ch) {
case AUX_CH_A:
case AUX_CH_B:
case AUX_CH_C:
case AUX_CH_USBC1:
case AUX_CH_USBC2:
case AUX_CH_USBC3:
case AUX_CH_USBC4:
case AUX_CH_USBC5: /* aka AUX_CH_D_XELPD */
case AUX_CH_USBC6: /* aka AUX_CH_E_XELPD */
return DP_AUX_CH_CTL(aux_ch);
default:
MISSING_CASE(aux_ch);
return DP_AUX_CH_CTL(AUX_CH_A);
}
}
static i915_reg_t tgl_aux_data_reg(struct intel_dp *intel_dp, int index)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
enum aux_ch aux_ch = dig_port->aux_ch;
switch (aux_ch) {
case AUX_CH_A:
case AUX_CH_B:
case AUX_CH_C:
case AUX_CH_USBC1:
case AUX_CH_USBC2:
case AUX_CH_USBC3:
case AUX_CH_USBC4:
case AUX_CH_USBC5: /* aka AUX_CH_D_XELPD */
case AUX_CH_USBC6: /* aka AUX_CH_E_XELPD */
return DP_AUX_CH_DATA(aux_ch, index);
default:
MISSING_CASE(aux_ch);
return DP_AUX_CH_DATA(AUX_CH_A, index);
}
}
void intel_dp_aux_fini(struct intel_dp *intel_dp)
{
if (cpu_latency_qos_request_active(&intel_dp->pm_qos))
cpu_latency_qos_remove_request(&intel_dp->pm_qos);
kfree(intel_dp->aux.name);
}
void intel_dp_aux_init(struct intel_dp *intel_dp)
{
struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
struct intel_encoder *encoder = &dig_port->base;
enum aux_ch aux_ch = dig_port->aux_ch;
if (DISPLAY_VER(dev_priv) >= 12) {
intel_dp->aux_ch_ctl_reg = tgl_aux_ctl_reg;
intel_dp->aux_ch_data_reg = tgl_aux_data_reg;
} else if (DISPLAY_VER(dev_priv) >= 9) {
intel_dp->aux_ch_ctl_reg = skl_aux_ctl_reg;
intel_dp->aux_ch_data_reg = skl_aux_data_reg;
} else if (HAS_PCH_SPLIT(dev_priv)) {
intel_dp->aux_ch_ctl_reg = ilk_aux_ctl_reg;
intel_dp->aux_ch_data_reg = ilk_aux_data_reg;
} else {
intel_dp->aux_ch_ctl_reg = g4x_aux_ctl_reg;
intel_dp->aux_ch_data_reg = g4x_aux_data_reg;
}
if (DISPLAY_VER(dev_priv) >= 9)
intel_dp->get_aux_clock_divider = skl_get_aux_clock_divider;
else if (IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
intel_dp->get_aux_clock_divider = hsw_get_aux_clock_divider;
else if (HAS_PCH_SPLIT(dev_priv))
intel_dp->get_aux_clock_divider = ilk_get_aux_clock_divider;
else
intel_dp->get_aux_clock_divider = g4x_get_aux_clock_divider;
if (DISPLAY_VER(dev_priv) >= 9)
intel_dp->get_aux_send_ctl = skl_get_aux_send_ctl;
else
intel_dp->get_aux_send_ctl = g4x_get_aux_send_ctl;
intel_dp->aux.drm_dev = &dev_priv->drm;
drm_dp_aux_init(&intel_dp->aux);
/* Failure to allocate our preferred name is not critical */
if (DISPLAY_VER(dev_priv) >= 13 && aux_ch >= AUX_CH_D_XELPD)
intel_dp->aux.name = kasprintf(GFP_KERNEL, "AUX %c/%s",
aux_ch_name(aux_ch - AUX_CH_D_XELPD + AUX_CH_D),
encoder->base.name);
else if (DISPLAY_VER(dev_priv) >= 12 && aux_ch >= AUX_CH_USBC1)
intel_dp->aux.name = kasprintf(GFP_KERNEL, "AUX USBC%c/%s",
aux_ch - AUX_CH_USBC1 + '1',
encoder->base.name);
else
intel_dp->aux.name = kasprintf(GFP_KERNEL, "AUX %c/%s",
aux_ch_name(aux_ch),
encoder->base.name);
intel_dp->aux.transfer = intel_dp_aux_transfer;
cpu_latency_qos_add_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
}