[PATCH 0/6 v4] adv7511 EDID probing improvements

[PATCH 0/6 v4] adv7511 EDID probing improvements

[John Stultz]

Wanted to re-send out v4  of this patch set, integrating some
changes suggested by Laurent, for consideration for merging for
v4.11

The first three patches are fixups that are hopefully straight
forward, integrating feedback I got from Laurant, with minimal
change from the previous versions.

The last three patches try to clean up and rework the EDID
probing code, to avoid issues seen on HiKey. I've reworked these
more significantly since v3 to address feedback from Laurent.

Thoughts and feedback would be appreciated!

thanks
-john

New in v4:
* Tweaked connector.status assignment to avoid race, as
  suggested by Laurent
* Reworked the __adv7511_power_on helpers to avoid calling
  regcache_sync in the EDID probe path
* Added new patch to set EDID_I2C_ADDR register before doing
  EDID read.

Cc: David Airlie <airlied@linux.ie>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org

Archit Taneja (1):
  drm/bridge: adv7511: Enable HPD interrupts to support hotplug and
    improve monitor detection

John Stultz (5):
  drm/bridge: adv7511: Use work_struct to defer hotplug handing to out
    of irq context
  drm/bridge: adv7511: Switch to using drm_kms_helper_hotplug_event()
  drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be
    reused internally
  drm/bridge: adv7511: Reuse __adv7511_power_on/off() when probing EDID
  drm/bridge: adv7511: Re-write the i2c address before EDID probing

 drivers/gpu/drm/bridge/adv7511/adv7511.h     |  2 +
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 67 ++++++++++++++++++++--------
 2 files changed, 51 insertions(+), 18 deletions(-)

-- 
2.7.4

[PATCH 1/6] drm/bridge: adv7511: Use work_struct to defer hotplug handing to out of irq context

[John Stultz]

I was recently seeing issues with EDID probing, where
the logic to wait for the EDID read bit to be set by the
IRQ wasn't happening and the code would time out and fail.

Digging deeper, I found this was due to the fact that
IRQs were disabled as we were running in IRQ context from
the HPD signal.

Thus this patch changes the logic to handle the HPD signal
via a work_struct so we can be out of irq context.

With this patch, the EDID probing on hotplug does not time
out.

Cc: David Airlie <airlied@linux.ie>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v3: Rename irq_work to hpd_work and remove extra whitespace, as
    suggested by Laurent
---
 drivers/gpu/drm/bridge/adv7511/adv7511.h     |  2 ++
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 11 ++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h b/drivers/gpu/drm/bridge/adv7511/adv7511.h
index 992d76c..0396791 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
@@ -317,6 +317,8 @@ struct adv7511 {
 	bool edid_read;
 
 	wait_queue_head_t wq;
+	struct work_struct hpd_work;
+
 	struct drm_bridge bridge;
 	struct drm_connector connector;
 
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index 8dba729..4fcea44 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -402,6 +402,13 @@ static bool adv7511_hpd(struct adv7511 *adv7511)
 	return false;
 }
 
+static void adv7511_hpd_work(struct work_struct *work)
+{
+	struct adv7511 *adv7511 = container_of(work, struct adv7511, hpd_work);
+
+	drm_helper_hpd_irq_event(adv7511->connector.dev);
+}
+
 static int adv7511_irq_process(struct adv7511 *adv7511, bool process_hpd)
 {
 	unsigned int irq0, irq1;
@@ -419,7 +426,7 @@ static int adv7511_irq_process(struct adv7511 *adv7511, bool process_hpd)
 	regmap_write(adv7511->regmap, ADV7511_REG_INT(1), irq1);
 
 	if (process_hpd && irq0 & ADV7511_INT0_HPD && adv7511->bridge.encoder)
-		drm_helper_hpd_irq_event(adv7511->connector.dev);
+		schedule_work(&adv7511->hpd_work);
 
 	if (irq0 & ADV7511_INT0_EDID_READY || irq1 & ADV7511_INT1_DDC_ERROR) {
 		adv7511->edid_read = true;
@@ -1006,6 +1013,8 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
 			goto err_i2c_unregister_edid;
 	}
 
+	INIT_WORK(&adv7511->hpd_work, adv7511_hpd_work);
+
 	if (i2c->irq) {
 		init_waitqueue_head(&adv7511->wq);
 
-- 
2.7.4

[PATCH 2/6] drm/bridge: adv7511: Switch to using drm_kms_helper_hotplug_event()

[John Stultz]

In chasing down a previous issue with EDID probing from calling
drm_helper_hpd_irq_event() from irq context, Laurent noticed
that the DRM documentation suggests that
drm_kms_helper_hotplug_event() should be used instead.

Thus this patch replaces drm_helper_hpd_irq_event() with
drm_kms_helper_hotplug_event(), which requires we update the
connector.status entry and only call _hotplug_event() when the
status changes.

Cc: David Airlie <airlied@linux.ie>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v3: Update connector.status value and only call __hotplug_event()
    when that status changes, as suggested by Laurent.
v4: Set adv7511->connector.status before calling
    adv7511->connector.status, as suggested by Laurent.
---
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index 4fcea44..7b2b5af 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -405,8 +405,22 @@ static bool adv7511_hpd(struct adv7511 *adv7511)
 static void adv7511_hpd_work(struct work_struct *work)
 {
 	struct adv7511 *adv7511 = container_of(work, struct adv7511, hpd_work);
+	enum drm_connector_status status;
+	unsigned int val;
+	int ret;
 
-	drm_helper_hpd_irq_event(adv7511->connector.dev);
+	ret = regmap_read(adv7511->regmap, ADV7511_REG_STATUS, &val);
+	if (ret < 0)
+		status = connector_status_disconnected;
+	else if (val & ADV7511_STATUS_HPD)
+		status = connector_status_connected;
+	else
+		status = connector_status_disconnected;
+
+	if (adv7511->connector.status != status) {
+		adv7511->connector.status = status;
+		drm_kms_helper_hotplug_event(adv7511->connector.dev);
+	}
 }
 
 static int adv7511_irq_process(struct adv7511 *adv7511, bool process_hpd)
-- 
2.7.4

[PATCH 3/6] drm/bridge: adv7511: Enable HPD interrupts to support hotplug and improve monitor detection

[John Stultz]

From: Archit Taneja <architt@codeaurora.org>

On some adv7511 implementations, we can get some spurious
disconnect signals which can cause monitor probing to fail.

This patch enables HPD (hot plug detect) interrupt support
which allows the monitor to be properly re-initialized when
the spurious disconnect signal goes away.

This also enables proper hotplug support.

Cc: David Airlie <airlied@linux.ie>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Originally-by: Archit Taneja <architt@codeaurora.org>
[jstultz: Added proper commit message]
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index 7b2b5af..405e460 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -338,7 +338,7 @@ static void adv7511_power_on(struct adv7511 *adv7511)
 		 * Still, let's be safe and stick to the documentation.
 		 */
 		regmap_write(adv7511->regmap, ADV7511_REG_INT_ENABLE(0),
-			     ADV7511_INT0_EDID_READY);
+			     ADV7511_INT0_EDID_READY | ADV7511_INT0_HPD);
 		regmap_write(adv7511->regmap, ADV7511_REG_INT_ENABLE(1),
 			     ADV7511_INT1_DDC_ERROR);
 	}
@@ -846,6 +846,10 @@ static int adv7511_bridge_attach(struct drm_bridge *bridge)
 	if (adv->type == ADV7533)
 		ret = adv7533_attach_dsi(adv);
 
+	if (adv->i2c_main->irq)
+		regmap_write(adv->regmap, ADV7511_REG_INT_ENABLE(0),
+				ADV7511_INT0_HPD);
+
 	return ret;
 }
 
-- 
2.7.4

[PATCH 4/6] drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be reused internally

[John Stultz]

In chasing down issues with EDID probing, I found some
duplicated but incomplete logic used to power the chip on and
off.

This patch refactors the adv7511_power_on/off functions, so
they can be used for internal needs.

Cc: David Airlie <airlied@linux.ie>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v4: Move the regcache_sync() call outside the shared
    implementation as we don't want to call it on EDID probing,
    as suggested by Laurent
---
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index 405e460..12f2876 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -325,7 +325,7 @@ static void adv7511_set_link_config(struct adv7511 *adv7511,
 	adv7511->rgb = config->input_colorspace == HDMI_COLORSPACE_RGB;
 }
 
-static void adv7511_power_on(struct adv7511 *adv7511)
+static void __adv7511_power_on(struct adv7511 *adv7511)
 {
 	adv7511->current_edid_segment = -1;
 
@@ -354,6 +354,11 @@ static void adv7511_power_on(struct adv7511 *adv7511)
 	regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER2,
 			   ADV7511_REG_POWER2_HPD_SRC_MASK,
 			   ADV7511_REG_POWER2_HPD_SRC_NONE);
+}
+
+static void adv7511_power_on(struct adv7511 *adv7511)
+{
+	__adv7511_power_on(adv7511);
 
 	/*
 	 * Most of the registers are reset during power down or when HPD is low.
@@ -362,21 +367,23 @@ static void adv7511_power_on(struct adv7511 *adv7511)
 
 	if (adv7511->type == ADV7533)
 		adv7533_dsi_power_on(adv7511);
-
 	adv7511->powered = true;
 }
 
-static void adv7511_power_off(struct adv7511 *adv7511)
+static void __adv7511_power_off(struct adv7511 *adv7511)
 {
 	/* TODO: setup additional power down modes */
 	regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER,
 			   ADV7511_POWER_POWER_DOWN,
 			   ADV7511_POWER_POWER_DOWN);
 	regcache_mark_dirty(adv7511->regmap);
+}
 
+static void adv7511_power_off(struct adv7511 *adv7511)
+{
+	__adv7511_power_off(adv7511);
 	if (adv7511->type == ADV7533)
 		adv7533_dsi_power_off(adv7511);
-
 	adv7511->powered = false;
 }
 
-- 
2.7.4

Re: [PATCH 4/6] drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be reused internally

[Laurent Pinchart]

Hi John,

Thank you for the patch.

On Monday 16 Jan 2017 16:52:50 John Stultz wrote:
> In chasing down issues with EDID probing, I found some
> duplicated but incomplete logic used to power the chip on and
> off.
> 
> This patch refactors the adv7511_power_on/off functions, so
> they can be used for internal needs.
> 
> Cc: David Airlie <airlied@linux.ie>
> Cc: Archit Taneja <architt@codeaurora.org>
> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Cc: Lars-Peter Clausen <lars@metafoo.de>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: John Stultz <john.stultz@linaro.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
> v4: Move the regcache_sync() call outside the shared
>     implementation as we don't want to call it on EDID probing,
>     as suggested by Laurent
> ---
>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 405e460..12f2876
> 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -325,7 +325,7 @@ static void adv7511_set_link_config(struct adv7511
> *adv7511, adv7511->rgb = config->input_colorspace == HDMI_COLORSPACE_RGB;
>  }
> 
> -static void adv7511_power_on(struct adv7511 *adv7511)
> +static void __adv7511_power_on(struct adv7511 *adv7511)
>  {
>  	adv7511->current_edid_segment = -1;
> 
> @@ -354,6 +354,11 @@ static void adv7511_power_on(struct adv7511 *adv7511)
>  	regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER2,
>  			   ADV7511_REG_POWER2_HPD_SRC_MASK,
>  			   ADV7511_REG_POWER2_HPD_SRC_NONE);
> +}
> +
> +static void adv7511_power_on(struct adv7511 *adv7511)
> +{
> +	__adv7511_power_on(adv7511);
> 
>  	/*
>  	 * Most of the registers are reset during power down or when HPD is 
low.
> @@ -362,21 +367,23 @@ static void adv7511_power_on(struct adv7511 *adv7511)
> 
>  	if (adv7511->type == ADV7533)
>  		adv7533_dsi_power_on(adv7511);
> -
>  	adv7511->powered = true;
>  }
> 
> -static void adv7511_power_off(struct adv7511 *adv7511)
> +static void __adv7511_power_off(struct adv7511 *adv7511)
>  {
>  	/* TODO: setup additional power down modes */
>  	regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER,
>  			   ADV7511_POWER_POWER_DOWN,
>  			   ADV7511_POWER_POWER_DOWN);
>  	regcache_mark_dirty(adv7511->regmap);
> +}
> 
> +static void adv7511_power_off(struct adv7511 *adv7511)
> +{
> +	__adv7511_power_off(adv7511);
>  	if (adv7511->type == ADV7533)
>  		adv7533_dsi_power_off(adv7511);
> -
>  	adv7511->powered = false;
>  }

-- 
Regards,

Laurent Pinchart

[PATCH 5/6] drm/bridge: adv7511: Reuse __adv7511_power_on/off() when probing EDID

[John Stultz]

Thus this patch changes the EDID probing logic so that we
re-use the __adv7511_power_on/off() calls instead of duplciating
logic.

This does change behavior slightly as it adds the HPD signal
pulse to the EDID probe path, but Archit has had a patch to
add HPD signal pulse to the EDID probe path before, so this
should address the cases where that helped.

Cc: David Airlie <airlied@linux.ie>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v4: Reworded commit message, focusing on re-use and HPD pulse
    behavior change.
---
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index 12f2876..d216f61 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -573,24 +573,13 @@ static int adv7511_get_modes(struct adv7511 *adv7511,
 	unsigned int count;
 
 	/* Reading the EDID only works if the device is powered */
-	if (!adv7511->powered) {
-		regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER,
-				   ADV7511_POWER_POWER_DOWN, 0);
-		if (adv7511->i2c_main->irq) {
-			regmap_write(adv7511->regmap, ADV7511_REG_INT_ENABLE(0),
-				     ADV7511_INT0_EDID_READY);
-			regmap_write(adv7511->regmap, ADV7511_REG_INT_ENABLE(1),
-				     ADV7511_INT1_DDC_ERROR);
-		}
-		adv7511->current_edid_segment = -1;
-	}
+	if (!adv7511->powered)
+		__adv7511_power_on(adv7511);
 
 	edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
 
 	if (!adv7511->powered)
-		regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER,
-				   ADV7511_POWER_POWER_DOWN,
-				   ADV7511_POWER_POWER_DOWN);
+		__adv7511_power_off(adv7511);
 
 	kfree(adv7511->edid);
 	adv7511->edid = edid;
-- 
2.7.4

Re: [PATCH 5/6] drm/bridge: adv7511: Reuse __adv7511_power_on/off() when probing EDID

[Laurent Pinchart]

Hi John,

Thank you for the patch.

On Monday 16 Jan 2017 16:52:51 John Stultz wrote:
> Thus this patch changes the EDID probing logic so that we
> re-use the __adv7511_power_on/off() calls instead of duplciating
> logic.
> 
> This does change behavior slightly as it adds the HPD signal
> pulse to the EDID probe path, but Archit has had a patch to
> add HPD signal pulse to the EDID probe path before, so this
> should address the cases where that helped.

You should also mentioned that the power off path now calls 
regcache_mark_dirty(). Apart from that,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> Cc: David Airlie <airlied@linux.ie>
> Cc: Archit Taneja <architt@codeaurora.org>
> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Cc: Lars-Peter Clausen <lars@metafoo.de>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
> v4: Reworded commit message, focusing on re-use and HPD pulse
>     behavior change.
> ---
>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 17 +++--------------
>  1 file changed, 3 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index 12f2876..d216f61
> 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -573,24 +573,13 @@ static int adv7511_get_modes(struct adv7511 *adv7511,
>  	unsigned int count;
> 
>  	/* Reading the EDID only works if the device is powered */
> -	if (!adv7511->powered) {
> -		regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER,
> -				   ADV7511_POWER_POWER_DOWN, 0);
> -		if (adv7511->i2c_main->irq) {
> -			regmap_write(adv7511->regmap, 
ADV7511_REG_INT_ENABLE(0),
> -				     ADV7511_INT0_EDID_READY);
> -			regmap_write(adv7511->regmap, 
ADV7511_REG_INT_ENABLE(1),
> -				     ADV7511_INT1_DDC_ERROR);
> -		}
> -		adv7511->current_edid_segment = -1;
> -	}
> +	if (!adv7511->powered)
> +		__adv7511_power_on(adv7511);
> 
>  	edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
> 
>  	if (!adv7511->powered)
> -		regmap_update_bits(adv7511->regmap, ADV7511_REG_POWER,
> -				   ADV7511_POWER_POWER_DOWN,
> -				   ADV7511_POWER_POWER_DOWN);
> +		__adv7511_power_off(adv7511);
> 
>  	kfree(adv7511->edid);
>  	adv7511->edid = edid;

-- 
Regards,

Laurent Pinchart

[PATCH 6/6] drm/bridge: adv7511: Re-write the i2c address before EDID probing

[John Stultz]

I've found that by just turning the chip on and off via the
POWER_DOWN register, I end up getting i2c_transfer errors on
HiKey.

Investigating further, it seems some of the register state in
the regmap cache is getting lost, likely as the device registers
were reset during power off.

Thus this patch simply re-writes the i2c address to the
ADV7511_REG_EDID_I2C_ADDR register to ensure its properly set
before we try to read the EDID data.

Cc: David Airlie <airlied@linux.ie>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v4: New approach to make the EDID_I2C_ADDR register
    sane, as suggested by Laurent
---
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index d216f61..0ed89ea 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -573,9 +573,17 @@ static int adv7511_get_modes(struct adv7511 *adv7511,
 	unsigned int count;
 
 	/* Reading the EDID only works if the device is powered */
-	if (!adv7511->powered)
+	if (!adv7511->powered) {
+		unsigned int edid_i2c_addr =
+					(adv7511->i2c_main->addr << 1) + 4;
+
 		__adv7511_power_on(adv7511);
 
+		/* Reset the EDID_I2C_ADDR register as it might be cleared */
+		regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR,
+			     edid_i2c_addr);
+	}
+
 	edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
 
 	if (!adv7511->powered)
-- 
2.7.4

Re: [PATCH 6/6] drm/bridge: adv7511: Re-write the i2c address before EDID probing

[Laurent Pinchart]

Hi John,

Thank you for the patch.

On Monday 16 Jan 2017 16:52:52 John Stultz wrote:
> I've found that by just turning the chip on and off via the
> POWER_DOWN register, I end up getting i2c_transfer errors on
> HiKey.
> 
> Investigating further, it seems some of the register state in
> the regmap cache is getting lost, likely as the device registers
> were reset during power off.

It's not the state in the regmap cache that is lost, but the state in the 
hardware, indeed because the registers contents are lost when the chip is 
powered down.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> Thus this patch simply re-writes the i2c address to the
> ADV7511_REG_EDID_I2C_ADDR register to ensure its properly set
> before we try to read the EDID data.
> 
> Cc: David Airlie <airlied@linux.ie>
> Cc: Archit Taneja <architt@codeaurora.org>
> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Cc: Lars-Peter Clausen <lars@metafoo.de>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
> v4: New approach to make the EDID_I2C_ADDR register
>     sane, as suggested by Laurent
> ---
>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index d216f61..0ed89ea
> 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -573,9 +573,17 @@ static int adv7511_get_modes(struct adv7511 *adv7511,
>  	unsigned int count;
> 
>  	/* Reading the EDID only works if the device is powered */
> -	if (!adv7511->powered)
> +	if (!adv7511->powered) {
> +		unsigned int edid_i2c_addr =
> +					(adv7511->i2c_main->addr << 1) + 4;
> +
>  		__adv7511_power_on(adv7511);
> 
> +		/* Reset the EDID_I2C_ADDR register as it might be cleared */
> +		regmap_write(adv7511->regmap, ADV7511_REG_EDID_I2C_ADDR,
> +			     edid_i2c_addr);
> +	}
> +
>  	edid = drm_do_get_edid(connector, adv7511_get_edid_block, adv7511);
> 
>  	if (!adv7511->powered)

-- 
Regards,

Laurent Pinchart

Re: [PATCH 0/6 v4] adv7511 EDID probing improvements

[Laurent Pinchart]

Hi John,

Thank you for the patches.

On Monday 16 Jan 2017 16:52:46 John Stultz wrote:
> Wanted to re-send out v4  of this patch set, integrating some
> changes suggested by Laurent, for consideration for merging for
> v4.11
> 
> The first three patches are fixups that are hopefully straight
> forward, integrating feedback I got from Laurant, with minimal
> change from the previous versions.
> 
> The last three patches try to clean up and rework the EDID
> probing code, to avoid issues seen on HiKey. I've reworked these
> more significantly since v3 to address feedback from Laurent.
> 
> Thoughts and feedback would be appreciated!

For the whole series,

Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> New in v4:
> * Tweaked connector.status assignment to avoid race, as
>   suggested by Laurent
> * Reworked the __adv7511_power_on helpers to avoid calling
>   regcache_sync in the EDID probe path
> * Added new patch to set EDID_I2C_ADDR register before doing
>   EDID read.
> 
> Cc: David Airlie <airlied@linux.ie>
> Cc: Archit Taneja <architt@codeaurora.org>
> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Cc: Lars-Peter Clausen <lars@metafoo.de>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: dri-devel@lists.freedesktop.org
> 
> Archit Taneja (1):
>   drm/bridge: adv7511: Enable HPD interrupts to support hotplug and
>     improve monitor detection
> 
> John Stultz (5):
>   drm/bridge: adv7511: Use work_struct to defer hotplug handing to out
>     of irq context
>   drm/bridge: adv7511: Switch to using drm_kms_helper_hotplug_event()
>   drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be
>     reused internally
>   drm/bridge: adv7511: Reuse __adv7511_power_on/off() when probing EDID
>   drm/bridge: adv7511: Re-write the i2c address before EDID probing
> 
>  drivers/gpu/drm/bridge/adv7511/adv7511.h     |  2 +
>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 67
> ++++++++++++++++++++-------- 2 files changed, 51 insertions(+), 18
> deletions(-)

-- 
Regards,

Laurent Pinchart

Re: [PATCH 0/6 v4] adv7511 EDID probing improvements

[Archit Taneja]

On 01/19/2017 04:34 AM, Laurent Pinchart wrote:
> Hi John,
>
> Thank you for the patches.
>
> On Monday 16 Jan 2017 16:52:46 John Stultz wrote:
>> Wanted to re-send out v4  of this patch set, integrating some
>> changes suggested by Laurent, for consideration for merging for
>> v4.11
>>
>> The first three patches are fixups that are hopefully straight
>> forward, integrating feedback I got from Laurant, with minimal
>> change from the previous versions.
>>
>> The last three patches try to clean up and rework the EDID
>> probing code, to avoid issues seen on HiKey. I've reworked these
>> more significantly since v3 to address feedback from Laurent.
>>
>> Thoughts and feedback would be appreciated!
>
> For the whole series,
>
> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Queued to drm-misc-next. Updated the commit messages for patches 5
and 6 as suggested by Laurent.

Thanks,
Archit

>
>> New in v4:
>> * Tweaked connector.status assignment to avoid race, as
>>   suggested by Laurent
>> * Reworked the __adv7511_power_on helpers to avoid calling
>>   regcache_sync in the EDID probe path
>> * Added new patch to set EDID_I2C_ADDR register before doing
>>   EDID read.
>>
>> Cc: David Airlie <airlied@linux.ie>
>> Cc: Archit Taneja <architt@codeaurora.org>
>> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
>> Cc: Lars-Peter Clausen <lars@metafoo.de>
>> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>> Cc: dri-devel@lists.freedesktop.org
>>
>> Archit Taneja (1):
>>   drm/bridge: adv7511: Enable HPD interrupts to support hotplug and
>>     improve monitor detection
>>
>> John Stultz (5):
>>   drm/bridge: adv7511: Use work_struct to defer hotplug handing to out
>>     of irq context
>>   drm/bridge: adv7511: Switch to using drm_kms_helper_hotplug_event()
>>   drm/bridge: adv7511: Rework adv7511_power_on/off() so they can be
>>     reused internally
>>   drm/bridge: adv7511: Reuse __adv7511_power_on/off() when probing EDID
>>   drm/bridge: adv7511: Re-write the i2c address before EDID probing
>>
>>  drivers/gpu/drm/bridge/adv7511/adv7511.h     |  2 +
>>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 67
>> ++++++++++++++++++++-------- 2 files changed, 51 insertions(+), 18
>> deletions(-)
>

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH 0/6 v4] adv7511 EDID probing improvements

[John Stultz]

On Wed, Jan 18, 2017 at 9:22 PM, Archit Taneja <architt@codeaurora.org> wrote:
>
>
> On 01/19/2017 04:34 AM, Laurent Pinchart wrote:
>>
>> Hi John,
>>
>> Thank you for the patches.
>>
>> On Monday 16 Jan 2017 16:52:46 John Stultz wrote:
>>>
>>> Wanted to re-send out v4  of this patch set, integrating some
>>> changes suggested by Laurent, for consideration for merging for
>>> v4.11
>>>
>>> The first three patches are fixups that are hopefully straight
>>> forward, integrating feedback I got from Laurant, with minimal
>>> change from the previous versions.
>>>
>>> The last three patches try to clean up and rework the EDID
>>> probing code, to avoid issues seen on HiKey. I've reworked these
>>> more significantly since v3 to address feedback from Laurent.
>>>
>>> Thoughts and feedback would be appreciated!
>>
>>
>> For the whole series,
>>
>> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
>
> Queued to drm-misc-next. Updated the commit messages for patches 5
> and 6 as suggested by Laurent.

Ah! Many thanks Archit! I was going to respin the patches tomorrow but
you beat me to it. :)

The help is much appreciated!
-john