[12/41] drm/bridge: analogix_dp: add fast link train for eDP
diff mbox

Message ID 20170310043305.17216-13-seanpaul@chromium.org
State New
Headers show

Commit Message

Sean Paul March 10, 2017, 4:32 a.m. UTC
From: zain wang <wzz@rock-chips.com>

We would meet a short black screen when exit PSR with the full link
training, In this case, we should use fast link train instead of full
link training.

Signed-off-by: zain wang <wzz@rock-chips.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 142 ++++++++++++++++-----
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |   3 +
 2 files changed, 114 insertions(+), 31 deletions(-)

Comments

Andrzej Hajda March 16, 2017, 2:14 p.m. UTC | #1
On 10.03.2017 05:32, Sean Paul wrote:
> From: zain wang <wzz@rock-chips.com>
>
> We would meet a short black screen when exit PSR with the full link
> training, In this case, we should use fast link train instead of full
> link training.
>
> Signed-off-by: zain wang <wzz@rock-chips.com>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
> ---
>  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 142 ++++++++++++++++-----
>  drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |   3 +
>  2 files changed, 114 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 64d94a34874d..5bc151b0995b 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -10,17 +10,18 @@
>  * option) any later version.
>  */
>  
> -#include <linux/module.h>
> -#include <linux/platform_device.h>
> -#include <linux/err.h>
>  #include <linux/clk.h>
> -#include <linux/io.h>
> +#include <linux/component.h>
> +#include <linux/err.h>
> +#include <linux/gpio.h>
>  #include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_gpio.h>
> -#include <linux/gpio.h>
> -#include <linux/component.h>
>  #include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
>  
>  #include <drm/drmP.h>
>  #include <drm/drm_atomic_helper.h>
> @@ -35,6 +36,8 @@
>  
>  #define to_dp(nm)	container_of(nm, struct analogix_dp_device, nm)
>  
> +static const bool verify_fast_training;
> +

Quite odd debug sentinel, I am not sure if it is good practice to use
such construct.

>  struct bridge_init {
>  	struct i2c_client *client;
>  	struct device_node *node;
> @@ -531,7 +534,7 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
>  {
>  	int lane, lane_count, retval;
>  	u32 reg;
> -	u8 link_align, link_status[2], adjust_request[2];
> +	u8 link_align, link_status[2], adjust_request[2], spread;
>  
>  	usleep_range(400, 401);
>  
> @@ -574,6 +577,20 @@ static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
>  		dev_dbg(dp->dev, "final lane count = %.2x\n",
>  			dp->link_train.lane_count);
>  
> +		retval = drm_dp_dpcd_readb(&dp->aux, DP_MAX_DOWNSPREAD,
> +					   &spread);
> +		if (retval != 1) {
> +			dev_err(dp->dev, "failed to read downspread %d\n",

comma before %d ?

> +				retval);
> +			dp->fast_train_support = false;
> +		} else {
> +			dp->fast_train_support =
> +				(spread & DP_NO_AUX_HANDSHAKE_LINK_TRAINING) ?
> +					true : false;

dp->fast_train_support = !!(spread & DP_NO_AUX_HANDSHAKE_LINK_TRAINING);
or even
dp->fast_train_support = spread & DP_NO_AUX_HANDSHAKE_LINK_TRAINING;
if dp->fast_train_support is bool

> +		}
> +		dev_dbg(dp->dev, "fast link training %s\n",
> +			dp->fast_train_support ? "supported" : "unsupported");
> +
>  		/* set enhanced mode if available */
>  		analogix_dp_set_enhanced_mode(dp);
>  		dp->link_train.lt_state = FINISHED;
> @@ -630,10 +647,12 @@ static void analogix_dp_get_max_rx_lane_count(struct analogix_dp_device *dp,
>  	*lane_count = DPCD_MAX_LANE_COUNT(data);
>  }
>  
> -static void analogix_dp_init_training(struct analogix_dp_device *dp,
> -				      enum link_lane_count_type max_lane,
> -				      int max_rate)
> +static int analogix_dp_full_link_train(struct analogix_dp_device *dp,
> +				       u32 max_lanes, u32 max_rate)
>  {
> +	int retval = 0;
> +	bool training_finished = false;
> +
>  	/*
>  	 * MACRO_RST must be applied after the PLL_LOCK to avoid
>  	 * the DP inter pair skew issue for at least 10 us
> @@ -659,18 +678,13 @@ static void analogix_dp_init_training(struct analogix_dp_device *dp,
>  	}
>  
>  	/* Setup TX lane count & rate */
> -	if (dp->link_train.lane_count > max_lane)
> -		dp->link_train.lane_count = max_lane;
> +	if (dp->link_train.lane_count > max_lanes)
> +		dp->link_train.lane_count = max_lanes;
>  	if (dp->link_train.link_rate > max_rate)
>  		dp->link_train.link_rate = max_rate;
>  
>  	/* All DP analog module power up */
>  	analogix_dp_set_analog_power_down(dp, POWER_ALL, 0);
> -}
> -
> -static int analogix_dp_sw_link_training(struct analogix_dp_device *dp)
> -{
> -	int retval = 0, training_finished = 0;
>  
>  	dp->link_train.lt_state = START;
>  
> @@ -705,22 +719,88 @@ static int analogix_dp_sw_link_training(struct analogix_dp_device *dp)
>  	return retval;
>  }
>  
> -static int analogix_dp_set_link_train(struct analogix_dp_device *dp,
> -				      u32 count, u32 bwtype)
> +static int analogix_dp_fast_link_train(struct analogix_dp_device *dp)
>  {
> -	int i;
> -	int retval;
> +	int i, ret;
> +	u8 link_align, link_status[2];
> +	enum pll_status status;
>  
> -	for (i = 0; i < DP_TIMEOUT_LOOP_COUNT; i++) {
> -		analogix_dp_init_training(dp, count, bwtype);
> -		retval = analogix_dp_sw_link_training(dp);
> -		if (retval == 0)
> -			break;
> +	analogix_dp_reset_macro(dp);
>  
> -		usleep_range(100, 110);
> +	analogix_dp_set_link_bandwidth(dp, dp->link_train.link_rate);
> +	analogix_dp_set_lane_count(dp, dp->link_train.lane_count);
> +
> +	for (i = 0; i < dp->link_train.lane_count; i++) {
> +		analogix_dp_set_lane_link_training(dp,
> +			dp->link_train.training_lane[i], i);
>  	}
>  
> -	return retval;
> +	ret = readx_poll_timeout(analogix_dp_get_pll_lock_status, dp, status,
> +				 status != PLL_UNLOCKED, 120,
> +				 120 * DP_TIMEOUT_LOOP_COUNT);
> +	if (ret) {
> +		DRM_DEV_ERROR(dp->dev, "Wait for pll lock failed %d\n", ret);
> +		return ret;
> +	}
> +
> +	/* source Set training pattern 1 */
> +	analogix_dp_set_training_pattern(dp, TRAINING_PTN1);
> +	/* From DP spec, pattern must be on-screen for a minimum 500us */
> +	usleep_range(500, 600);
> +
> +	analogix_dp_set_training_pattern(dp, TRAINING_PTN2);
> +	/* From DP spec, pattern must be on-screen for a minimum 500us */
> +	usleep_range(500, 600);
> +
> +	/* TODO: enhanced_mode?*/
> +	analogix_dp_set_training_pattern(dp, DP_NONE);
> +
> +	/*
> +	 * Useful for debugging issues with fast link training, disable for more
> +	 * speed
> +	 */
> +	if (verify_fast_training) {
 You can move definitions of link_status and other local variables here.
> +		ret = drm_dp_dpcd_readb(&dp->aux, DP_LANE_ALIGN_STATUS_UPDATED,
> +					&link_align);
> +		if (ret < 0) {
> +			DRM_DEV_ERROR(dp->dev, "Read align status failed %d\n",
> +				      ret);
> +			return ret;
> +		}
> +
> +		ret = drm_dp_dpcd_read(&dp->aux, DP_LANE0_1_STATUS, link_status,
> +				       2);
> +		if (ret < 0) {
> +			DRM_DEV_ERROR(dp->dev, "Read link status failed %d\n",
> +				      ret);
> +			return ret;
> +		}
> +
> +		if (analogix_dp_clock_recovery_ok(link_status,
> +						  dp->link_train.lane_count)) {
> +			DRM_DEV_ERROR(dp->dev, "Clock recovery failed\n");
> +			analogix_dp_reduce_link_rate(dp);
> +			return -EIO;
> +		}
> +
> +		if (analogix_dp_channel_eq_ok(link_status, link_align,
> +					      dp->link_train.lane_count)) {
> +			DRM_DEV_ERROR(dp->dev, "Channel EQ failed\n");
> +			analogix_dp_reduce_link_rate(dp);
> +			return -EIO;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int analogix_dp_train_link(struct analogix_dp_device *dp)
> +{
> +	if (dp->fast_train_support)
> +		return analogix_dp_fast_link_train(dp);
> +
> +	return analogix_dp_full_link_train(dp, dp->video_info.max_lane_count,
> +					   dp->video_info.max_link_rate);
>  }
>  
>  static int analogix_dp_config_video(struct analogix_dp_device *dp)
> @@ -853,10 +933,10 @@ static void analogix_dp_commit(struct analogix_dp_device *dp)
>  			DRM_ERROR("failed to disable the panel\n");
>  	}
>  
> -	ret = analogix_dp_set_link_train(dp, dp->video_info.max_lane_count,
> -					 dp->video_info.max_link_rate);
> +	ret = readx_poll_timeout(analogix_dp_train_link, dp, ret, !ret, 100,
> +				 DP_TIMEOUT_TRAINING_US * 5);
>  	if (ret) {
> -		dev_err(dp->dev, "unable to do link train\n");
> +		dev_err(dp->dev, "unable to do link train, ret=%d\n", ret);

And here we have ", ret=%d\n". Maybe it would be good to make it
consistent across whole driver.
Another issue with consistency in DRM_DEV_ERROR vs dev_err.

Regards
Andrzej

>  		return;
>  	}
>  
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index e135a42cb19e..920607d7eb3e 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -20,6 +20,8 @@
>  #define MAX_CR_LOOP 5
>  #define MAX_EQ_LOOP 5
>  
> +/* Training takes 22ms if AUX channel comm fails. Use this as retry interval */
> +#define DP_TIMEOUT_TRAINING_US			22000
>  #define DP_TIMEOUT_PSR_LOOP_MS			300
>  
>  /* DP_MAX_LANE_COUNT */
> @@ -171,6 +173,7 @@ struct analogix_dp_device {
>  	int			hpd_gpio;
>  	bool                    force_hpd;
>  	bool			psr_enable;
> +	bool			fast_train_support;
>  
>  	struct mutex		panel_lock;
>  	bool			panel_is_modeset;
Sean Paul March 21, 2017, 8:37 p.m. UTC | #2
On Thu, Mar 16, 2017 at 03:14:28PM +0100, Andrzej Hajda wrote:
> On 10.03.2017 05:32, Sean Paul wrote:
> > From: zain wang <wzz@rock-chips.com>
> >
> > We would meet a short black screen when exit PSR with the full link
> > training, In this case, we should use fast link train instead of full
> > link training.
> >
> > Signed-off-by: zain wang <wzz@rock-chips.com>
> > Signed-off-by: Sean Paul <seanpaul@chromium.org>
> > ---
> >  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 142 ++++++++++++++++-----
> >  drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |   3 +
> >  2 files changed, 114 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > index 64d94a34874d..5bc151b0995b 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> > @@ -10,17 +10,18 @@
> >  * option) any later version.
> >  */
> >  
> > -#include <linux/module.h>
> > -#include <linux/platform_device.h>
> > -#include <linux/err.h>
> >  #include <linux/clk.h>
> > -#include <linux/io.h>
> > +#include <linux/component.h>
> > +#include <linux/err.h>
> > +#include <linux/gpio.h>
> >  #include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/of_gpio.h>
> > -#include <linux/gpio.h>
> > -#include <linux/component.h>
> >  #include <linux/phy/phy.h>
> > +#include <linux/platform_device.h>
> >  
> >  #include <drm/drmP.h>
> >  #include <drm/drm_atomic_helper.h>
> > @@ -35,6 +36,8 @@
> >  
> >  #define to_dp(nm)	container_of(nm, struct analogix_dp_device, nm)
> >  
> > +static const bool verify_fast_training;
> > +
> 
> Quite odd debug sentinel, I am not sure if it is good practice to use
> such construct.

IIRC, they originally had a #define and then used #ifdef below to gate the
verification. My concern with that was the code would rot if it wasn't compiled.

<snip>

> > @@ -853,10 +933,10 @@ static void analogix_dp_commit(struct analogix_dp_device *dp)
> >  			DRM_ERROR("failed to disable the panel\n");
> >  	}
> >  
> > -	ret = analogix_dp_set_link_train(dp, dp->video_info.max_lane_count,
> > -					 dp->video_info.max_link_rate);
> > +	ret = readx_poll_timeout(analogix_dp_train_link, dp, ret, !ret, 100,
> > +				 DP_TIMEOUT_TRAINING_US * 5);
> >  	if (ret) {
> > -		dev_err(dp->dev, "unable to do link train\n");
> > +		dev_err(dp->dev, "unable to do link train, ret=%d\n", ret);
> 
> And here we have ", ret=%d\n". Maybe it would be good to make it
> consistent across whole driver.

Meh. I don't think it's worth bikeshedding over commas in error messages. I'm
just happy there are error checks/messages.


> Another issue with consistency in DRM_DEV_ERROR vs dev_err.

Yeah, that's annoying.

Sean

> 
> Regards
> Andrzej
> 
> >  		return;
> >  	}
> >  
> > diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> > index e135a42cb19e..920607d7eb3e 100644
> > --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> > +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> > @@ -20,6 +20,8 @@
> >  #define MAX_CR_LOOP 5
> >  #define MAX_EQ_LOOP 5
> >  
> > +/* Training takes 22ms if AUX channel comm fails. Use this as retry interval */
> > +#define DP_TIMEOUT_TRAINING_US			22000
> >  #define DP_TIMEOUT_PSR_LOOP_MS			300
> >  
> >  /* DP_MAX_LANE_COUNT */
> > @@ -171,6 +173,7 @@ struct analogix_dp_device {
> >  	int			hpd_gpio;
> >  	bool                    force_hpd;
> >  	bool			psr_enable;
> > +	bool			fast_train_support;
> >  
> >  	struct mutex		panel_lock;
> >  	bool			panel_is_modeset;
>
Andrzej Hajda March 22, 2017, 8:07 a.m. UTC | #3
On 21.03.2017 21:37, Sean Paul wrote:
> On Thu, Mar 16, 2017 at 03:14:28PM +0100, Andrzej Hajda wrote:
>> On 10.03.2017 05:32, Sean Paul wrote:
>>> From: zain wang <wzz@rock-chips.com>
>>>
>>> We would meet a short black screen when exit PSR with the full link
>>> training, In this case, we should use fast link train instead of full
>>> link training.
>>>
>>> Signed-off-by: zain wang <wzz@rock-chips.com>
>>> Signed-off-by: Sean Paul <seanpaul@chromium.org>
>>> ---
>>>  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 142 ++++++++++++++++-----
>>>  drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |   3 +
>>>  2 files changed, 114 insertions(+), 31 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>>> index 64d94a34874d..5bc151b0995b 100644
>>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
>>> @@ -10,17 +10,18 @@
>>>  * option) any later version.
>>>  */
>>>  
>>> -#include <linux/module.h>
>>> -#include <linux/platform_device.h>
>>> -#include <linux/err.h>
>>>  #include <linux/clk.h>
>>> -#include <linux/io.h>
>>> +#include <linux/component.h>
>>> +#include <linux/err.h>
>>> +#include <linux/gpio.h>
>>>  #include <linux/interrupt.h>
>>> +#include <linux/io.h>
>>> +#include <linux/iopoll.h>
>>> +#include <linux/module.h>
>>>  #include <linux/of.h>
>>>  #include <linux/of_gpio.h>
>>> -#include <linux/gpio.h>
>>> -#include <linux/component.h>
>>>  #include <linux/phy/phy.h>
>>> +#include <linux/platform_device.h>
>>>  
>>>  #include <drm/drmP.h>
>>>  #include <drm/drm_atomic_helper.h>
>>> @@ -35,6 +36,8 @@
>>>  
>>>  #define to_dp(nm)	container_of(nm, struct analogix_dp_device, nm)
>>>  
>>> +static const bool verify_fast_training;
>>> +
>> Quite odd debug sentinel, I am not sure if it is good practice to use
>> such construct.
> IIRC, they originally had a #define and then used #ifdef below to gate the
> verification. My concern with that was the code would rot if it wasn't compiled.

It just looks unusual, I am not strongly against current version.

>
> <snip>
>
>>> @@ -853,10 +933,10 @@ static void analogix_dp_commit(struct analogix_dp_device *dp)
>>>  			DRM_ERROR("failed to disable the panel\n");
>>>  	}
>>>  
>>> -	ret = analogix_dp_set_link_train(dp, dp->video_info.max_lane_count,
>>> -					 dp->video_info.max_link_rate);
>>> +	ret = readx_poll_timeout(analogix_dp_train_link, dp, ret, !ret, 100,
>>> +				 DP_TIMEOUT_TRAINING_US * 5);
>>>  	if (ret) {
>>> -		dev_err(dp->dev, "unable to do link train\n");
>>> +		dev_err(dp->dev, "unable to do link train, ret=%d\n", ret);
>> And here we have ", ret=%d\n". Maybe it would be good to make it
>> consistent across whole driver.
> Meh. I don't think it's worth bikeshedding over commas in error messages. I'm
> just happy there are error checks/messages.

But if there will be next iteration it is not big deal to fix it then :)

Regards
Andrzej

>
>
>> Another issue with consistency in DRM_DEV_ERROR vs dev_err.
> Yeah, that's annoying.
>
> Sean
>
>> Regards
>> Andrzej
>>
>>>  		return;
>>>  	}
>>>  
>>> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
>>> index e135a42cb19e..920607d7eb3e 100644
>>> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
>>> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
>>> @@ -20,6 +20,8 @@
>>>  #define MAX_CR_LOOP 5
>>>  #define MAX_EQ_LOOP 5
>>>  
>>> +/* Training takes 22ms if AUX channel comm fails. Use this as retry interval */
>>> +#define DP_TIMEOUT_TRAINING_US			22000
>>>  #define DP_TIMEOUT_PSR_LOOP_MS			300
>>>  
>>>  /* DP_MAX_LANE_COUNT */
>>> @@ -171,6 +173,7 @@ struct analogix_dp_device {
>>>  	int			hpd_gpio;
>>>  	bool                    force_hpd;
>>>  	bool			psr_enable;
>>> +	bool			fast_train_support;
>>>  
>>>  	struct mutex		panel_lock;
>>>  	bool			panel_is_modeset;

Patch
diff mbox

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 64d94a34874d..5bc151b0995b 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -10,17 +10,18 @@ 
 * option) any later version.
 */
 
-#include <linux/module.h>
-#include <linux/platform_device.h>
-#include <linux/err.h>
 #include <linux/clk.h>
-#include <linux/io.h>
+#include <linux/component.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
 #include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
-#include <linux/gpio.h>
-#include <linux/component.h>
 #include <linux/phy/phy.h>
+#include <linux/platform_device.h>
 
 #include <drm/drmP.h>
 #include <drm/drm_atomic_helper.h>
@@ -35,6 +36,8 @@ 
 
 #define to_dp(nm)	container_of(nm, struct analogix_dp_device, nm)
 
+static const bool verify_fast_training;
+
 struct bridge_init {
 	struct i2c_client *client;
 	struct device_node *node;
@@ -531,7 +534,7 @@  static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 {
 	int lane, lane_count, retval;
 	u32 reg;
-	u8 link_align, link_status[2], adjust_request[2];
+	u8 link_align, link_status[2], adjust_request[2], spread;
 
 	usleep_range(400, 401);
 
@@ -574,6 +577,20 @@  static int analogix_dp_process_equalizer_training(struct analogix_dp_device *dp)
 		dev_dbg(dp->dev, "final lane count = %.2x\n",
 			dp->link_train.lane_count);
 
+		retval = drm_dp_dpcd_readb(&dp->aux, DP_MAX_DOWNSPREAD,
+					   &spread);
+		if (retval != 1) {
+			dev_err(dp->dev, "failed to read downspread %d\n",
+				retval);
+			dp->fast_train_support = false;
+		} else {
+			dp->fast_train_support =
+				(spread & DP_NO_AUX_HANDSHAKE_LINK_TRAINING) ?
+					true : false;
+		}
+		dev_dbg(dp->dev, "fast link training %s\n",
+			dp->fast_train_support ? "supported" : "unsupported");
+
 		/* set enhanced mode if available */
 		analogix_dp_set_enhanced_mode(dp);
 		dp->link_train.lt_state = FINISHED;
@@ -630,10 +647,12 @@  static void analogix_dp_get_max_rx_lane_count(struct analogix_dp_device *dp,
 	*lane_count = DPCD_MAX_LANE_COUNT(data);
 }
 
-static void analogix_dp_init_training(struct analogix_dp_device *dp,
-				      enum link_lane_count_type max_lane,
-				      int max_rate)
+static int analogix_dp_full_link_train(struct analogix_dp_device *dp,
+				       u32 max_lanes, u32 max_rate)
 {
+	int retval = 0;
+	bool training_finished = false;
+
 	/*
 	 * MACRO_RST must be applied after the PLL_LOCK to avoid
 	 * the DP inter pair skew issue for at least 10 us
@@ -659,18 +678,13 @@  static void analogix_dp_init_training(struct analogix_dp_device *dp,
 	}
 
 	/* Setup TX lane count & rate */
-	if (dp->link_train.lane_count > max_lane)
-		dp->link_train.lane_count = max_lane;
+	if (dp->link_train.lane_count > max_lanes)
+		dp->link_train.lane_count = max_lanes;
 	if (dp->link_train.link_rate > max_rate)
 		dp->link_train.link_rate = max_rate;
 
 	/* All DP analog module power up */
 	analogix_dp_set_analog_power_down(dp, POWER_ALL, 0);
-}
-
-static int analogix_dp_sw_link_training(struct analogix_dp_device *dp)
-{
-	int retval = 0, training_finished = 0;
 
 	dp->link_train.lt_state = START;
 
@@ -705,22 +719,88 @@  static int analogix_dp_sw_link_training(struct analogix_dp_device *dp)
 	return retval;
 }
 
-static int analogix_dp_set_link_train(struct analogix_dp_device *dp,
-				      u32 count, u32 bwtype)
+static int analogix_dp_fast_link_train(struct analogix_dp_device *dp)
 {
-	int i;
-	int retval;
+	int i, ret;
+	u8 link_align, link_status[2];
+	enum pll_status status;
 
-	for (i = 0; i < DP_TIMEOUT_LOOP_COUNT; i++) {
-		analogix_dp_init_training(dp, count, bwtype);
-		retval = analogix_dp_sw_link_training(dp);
-		if (retval == 0)
-			break;
+	analogix_dp_reset_macro(dp);
 
-		usleep_range(100, 110);
+	analogix_dp_set_link_bandwidth(dp, dp->link_train.link_rate);
+	analogix_dp_set_lane_count(dp, dp->link_train.lane_count);
+
+	for (i = 0; i < dp->link_train.lane_count; i++) {
+		analogix_dp_set_lane_link_training(dp,
+			dp->link_train.training_lane[i], i);
 	}
 
-	return retval;
+	ret = readx_poll_timeout(analogix_dp_get_pll_lock_status, dp, status,
+				 status != PLL_UNLOCKED, 120,
+				 120 * DP_TIMEOUT_LOOP_COUNT);
+	if (ret) {
+		DRM_DEV_ERROR(dp->dev, "Wait for pll lock failed %d\n", ret);
+		return ret;
+	}
+
+	/* source Set training pattern 1 */
+	analogix_dp_set_training_pattern(dp, TRAINING_PTN1);
+	/* From DP spec, pattern must be on-screen for a minimum 500us */
+	usleep_range(500, 600);
+
+	analogix_dp_set_training_pattern(dp, TRAINING_PTN2);
+	/* From DP spec, pattern must be on-screen for a minimum 500us */
+	usleep_range(500, 600);
+
+	/* TODO: enhanced_mode?*/
+	analogix_dp_set_training_pattern(dp, DP_NONE);
+
+	/*
+	 * Useful for debugging issues with fast link training, disable for more
+	 * speed
+	 */
+	if (verify_fast_training) {
+		ret = drm_dp_dpcd_readb(&dp->aux, DP_LANE_ALIGN_STATUS_UPDATED,
+					&link_align);
+		if (ret < 0) {
+			DRM_DEV_ERROR(dp->dev, "Read align status failed %d\n",
+				      ret);
+			return ret;
+		}
+
+		ret = drm_dp_dpcd_read(&dp->aux, DP_LANE0_1_STATUS, link_status,
+				       2);
+		if (ret < 0) {
+			DRM_DEV_ERROR(dp->dev, "Read link status failed %d\n",
+				      ret);
+			return ret;
+		}
+
+		if (analogix_dp_clock_recovery_ok(link_status,
+						  dp->link_train.lane_count)) {
+			DRM_DEV_ERROR(dp->dev, "Clock recovery failed\n");
+			analogix_dp_reduce_link_rate(dp);
+			return -EIO;
+		}
+
+		if (analogix_dp_channel_eq_ok(link_status, link_align,
+					      dp->link_train.lane_count)) {
+			DRM_DEV_ERROR(dp->dev, "Channel EQ failed\n");
+			analogix_dp_reduce_link_rate(dp);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int analogix_dp_train_link(struct analogix_dp_device *dp)
+{
+	if (dp->fast_train_support)
+		return analogix_dp_fast_link_train(dp);
+
+	return analogix_dp_full_link_train(dp, dp->video_info.max_lane_count,
+					   dp->video_info.max_link_rate);
 }
 
 static int analogix_dp_config_video(struct analogix_dp_device *dp)
@@ -853,10 +933,10 @@  static void analogix_dp_commit(struct analogix_dp_device *dp)
 			DRM_ERROR("failed to disable the panel\n");
 	}
 
-	ret = analogix_dp_set_link_train(dp, dp->video_info.max_lane_count,
-					 dp->video_info.max_link_rate);
+	ret = readx_poll_timeout(analogix_dp_train_link, dp, ret, !ret, 100,
+				 DP_TIMEOUT_TRAINING_US * 5);
 	if (ret) {
-		dev_err(dp->dev, "unable to do link train\n");
+		dev_err(dp->dev, "unable to do link train, ret=%d\n", ret);
 		return;
 	}
 
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index e135a42cb19e..920607d7eb3e 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -20,6 +20,8 @@ 
 #define MAX_CR_LOOP 5
 #define MAX_EQ_LOOP 5
 
+/* Training takes 22ms if AUX channel comm fails. Use this as retry interval */
+#define DP_TIMEOUT_TRAINING_US			22000
 #define DP_TIMEOUT_PSR_LOOP_MS			300
 
 /* DP_MAX_LANE_COUNT */
@@ -171,6 +173,7 @@  struct analogix_dp_device {
 	int			hpd_gpio;
 	bool                    force_hpd;
 	bool			psr_enable;
+	bool			fast_train_support;
 
 	struct mutex		panel_lock;
 	bool			panel_is_modeset;