[PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Romain Perier]

Currently, the irq handler that monitores changes for HPD anx RX_SENSE
relies on the status of the bridge for updating the status of the HPD.
The update is done only when the bridge is enabled.

However, on Rockchip platforms we have found use cases where it could be
a problem. When HDMI is being used, turning off/on the screen or
unplugging/re-plugging the cable, the following simplified code path
will happen:

- dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
hdmi->disabled is false, then the handler will update the rxsense flag
accordingly.
- dw_hdmi_update_power() will be invoked with the mode
DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
called and the PHY will be desactivated (its pixel clocks and TMDS)

[...]

- dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
disabled.

- dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
currently disabled the HPD status won't be updated, so hdmi->rxsense
won't be changed. Even if the data part of the PHY is disabled, this
information coming from the HDMI Transmitter is correct and should be
saved.

[...]

- dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
enabled.
- dw_hdmi_update_power() will be called. As hdmi->force will be equal to
DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
field has not been updated by the irq handler, so it will be false and
DRM_FORCE_ON won't be put to hdmi->force.

Consequently, most of the time dw_hdmi_poweron() won't be called in this
use case, TMDS won't be re-enabled the PHY won't be re-initialized,
resulting in a "Signal not found".

This commit fixes the issue by removing the check for "!hdmi->disabled".
As already explained, even if the PHY is partially disabled, information
coming from HDMI Transmitter about HPD should be saved for a later use.

Signed-off-by: Romain Perier <romain.perier@collabora.com>
---

Note: Due to an email configuration issue, some of my patches were not
received on infradead.org or vger.kernel.org. It is now fixed, so I
resend this patch for this reason.

 drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
index 235ce7d..b621fc7 100644
--- a/drivers/gpu/drm/bridge/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/dw-hdmi.c
@@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
 	if (intr_stat &
 	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
 		mutex_lock(&hdmi->mutex);
-		if (!hdmi->disabled && !hdmi->force) {
+		if (!hdmi->force) {
 			/*
 			 * If the RX sense status indicates we're disconnected,
 			 * clear the software rxsense status.
-- 
2.9.3

[PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Romain Perier]

Currently, the irq handler that monitores changes for HPD anx RX_SENSE
relies on the status of the bridge for updating the status of the HPD.
The update is done only when the bridge is enabled.

However, on Rockchip platforms we have found use cases where it could be
a problem. When HDMI is being used, turning off/on the screen or
unplugging/re-plugging the cable, the following simplified code path
will happen:

- dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
hdmi->disabled is false, then the handler will update the rxsense flag
accordingly.
- dw_hdmi_update_power() will be invoked with the mode
DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
called and the PHY will be desactivated (its pixel clocks and TMDS)

[...]

- dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
disabled.

- dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
currently disabled the HPD status won't be updated, so hdmi->rxsense
won't be changed. Even if the data part of the PHY is disabled, this
information coming from the HDMI Transmitter is correct and should be
saved.

[...]

- dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
enabled.
- dw_hdmi_update_power() will be called. As hdmi->force will be equal to
DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
field has not been updated by the irq handler, so it will be false and
DRM_FORCE_ON won't be put to hdmi->force.

Consequently, most of the time dw_hdmi_poweron() won't be called in this
use case, TMDS won't be re-enabled the PHY won't be re-initialized,
resulting in a "Signal not found".

This commit fixes the issue by removing the check for "!hdmi->disabled".
As already explained, even if the PHY is partially disabled, information
coming from HDMI Transmitter about HPD should be saved for a later use.

Signed-off-by: Romain Perier <romain.perier@collabora.com>
---

Note: Due to an email configuration issue, some of my patches were not
received on infradead.org or vger.kernel.org. It is now fixed, so I
resend this patch for this reason.

 drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
index 235ce7d..b621fc7 100644
--- a/drivers/gpu/drm/bridge/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/dw-hdmi.c
@@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
 	if (intr_stat &
 	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
 		mutex_lock(&hdmi->mutex);
-		if (!hdmi->disabled && !hdmi->force) {
+		if (!hdmi->force) {
 			/*
 			 * If the RX sense status indicates we're disconnected,
 			 * clear the software rxsense status.
-- 
2.9.3

[PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Romain Perier]

Currently, the irq handler that monitores changes for HPD anx RX_SENSE
relies on the status of the bridge for updating the status of the HPD.
The update is done only when the bridge is enabled.

However, on Rockchip platforms we have found use cases where it could be
a problem. When HDMI is being used, turning off/on the screen or
unplugging/re-plugging the cable, the following simplified code path
will happen:

- dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
hdmi->disabled is false, then the handler will update the rxsense flag
accordingly.
- dw_hdmi_update_power() will be invoked with the mode
DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
called and the PHY will be desactivated (its pixel clocks and TMDS)

[...]

- dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
disabled.

- dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
currently disabled the HPD status won't be updated, so hdmi->rxsense
won't be changed. Even if the data part of the PHY is disabled, this
information coming from the HDMI Transmitter is correct and should be
saved.

[...]

- dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
enabled.
- dw_hdmi_update_power() will be called. As hdmi->force will be equal to
DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
field has not been updated by the irq handler, so it will be false and
DRM_FORCE_ON won't be put to hdmi->force.

Consequently, most of the time dw_hdmi_poweron() won't be called in this
use case, TMDS won't be re-enabled the PHY won't be re-initialized,
resulting in a "Signal not found".

This commit fixes the issue by removing the check for "!hdmi->disabled".
As already explained, even if the PHY is partially disabled, information
coming from HDMI Transmitter about HPD should be saved for a later use.

Signed-off-by: Romain Perier <romain.perier@collabora.com>
---

Note: Due to an email configuration issue, some of my patches were not
received on infradead.org or vger.kernel.org. It is now fixed, so I
resend this patch for this reason.

 drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
index 235ce7d..b621fc7 100644
--- a/drivers/gpu/drm/bridge/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/dw-hdmi.c
@@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
 	if (intr_stat &
 	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
 		mutex_lock(&hdmi->mutex);
-		if (!hdmi->disabled && !hdmi->force) {
+		if (!hdmi->force) {
 			/*
 			 * If the RX sense status indicates we're disconnected,
 			 * clear the software rxsense status.
-- 
2.9.3

Re: [PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Jose Abreu]

Hi Romain,


On 08-03-2017 08:15, Romain Perier wrote:
> Currently, the irq handler that monitores changes for HPD anx RX_SENSE
> relies on the status of the bridge for updating the status of the HPD.
> The update is done only when the bridge is enabled.
>
> However, on Rockchip platforms we have found use cases where it could be
> a problem. When HDMI is being used, turning off/on the screen or
> unplugging/re-plugging the cable, the following simplified code path
> will happen:
>
> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
> hdmi->disabled is false, then the handler will update the rxsense flag
> accordingly.
> - dw_hdmi_update_power() will be invoked with the mode
> DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
> called and the PHY will be desactivated (its pixel clocks and TMDS)
>
> [...]
>
> - dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
> disabled.
>
> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
> currently disabled the HPD status won't be updated, so hdmi->rxsense
> won't be changed. Even if the data part of the PHY is disabled, this
> information coming from the HDMI Transmitter is correct and should be
> saved.
>
> [...]
>
> - dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
> enabled.
> - dw_hdmi_update_power() will be called. As hdmi->force will be equal to
> DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
> field has not been updated by the irq handler, so it will be false and
> DRM_FORCE_ON won't be put to hdmi->force.
>
> Consequently, most of the time dw_hdmi_poweron() won't be called in this
> use case, TMDS won't be re-enabled the PHY won't be re-initialized,
> resulting in a "Signal not found".
>
> This commit fixes the issue by removing the check for "!hdmi->disabled".
> As already explained, even if the PHY is partially disabled, information
> coming from HDMI Transmitter about HPD should be saved for a later use.
>
> Signed-off-by: Romain Perier <romain.perier@collabora.com>
> ---
>
> Note: Due to an email configuration issue, some of my patches were not
> received on infradead.org or vger.kernel.org. It is now fixed, so I
> resend this patch for this reason.
>
>  drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
> index 235ce7d..b621fc7 100644
> --- a/drivers/gpu/drm/bridge/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c
> @@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>  	if (intr_stat &
>  	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
>  		mutex_lock(&hdmi->mutex);
> -		if (!hdmi->disabled && !hdmi->force) {
> +		if (!hdmi->force) {
>  			/*
>  			 * If the RX sense status indicates we're disconnected,
>  			 * clear the software rxsense status.

Makes sense but I think you need to make sure that phy will not
be enabled when bridge is disabled i.e. you should update rxsense
only.

Best regards,
Jose Miguel Abreu

Re: [PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Jose Abreu]

Hi Romain,


On 08-03-2017 08:15, Romain Perier wrote:
> Currently, the irq handler that monitores changes for HPD anx RX_SENSE
> relies on the status of the bridge for updating the status of the HPD.
> The update is done only when the bridge is enabled.
>
> However, on Rockchip platforms we have found use cases where it could be
> a problem. When HDMI is being used, turning off/on the screen or
> unplugging/re-plugging the cable, the following simplified code path
> will happen:
>
> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
> hdmi->disabled is false, then the handler will update the rxsense flag
> accordingly.
> - dw_hdmi_update_power() will be invoked with the mode
> DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
> called and the PHY will be desactivated (its pixel clocks and TMDS)
>
> [...]
>
> - dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
> disabled.
>
> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
> currently disabled the HPD status won't be updated, so hdmi->rxsense
> won't be changed. Even if the data part of the PHY is disabled, this
> information coming from the HDMI Transmitter is correct and should be
> saved.
>
> [...]
>
> - dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
> enabled.
> - dw_hdmi_update_power() will be called. As hdmi->force will be equal to
> DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
> field has not been updated by the irq handler, so it will be false and
> DRM_FORCE_ON won't be put to hdmi->force.
>
> Consequently, most of the time dw_hdmi_poweron() won't be called in this
> use case, TMDS won't be re-enabled the PHY won't be re-initialized,
> resulting in a "Signal not found".
>
> This commit fixes the issue by removing the check for "!hdmi->disabled".
> As already explained, even if the PHY is partially disabled, information
> coming from HDMI Transmitter about HPD should be saved for a later use.
>
> Signed-off-by: Romain Perier <romain.perier-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
> ---
>
> Note: Due to an email configuration issue, some of my patches were not
> received on infradead.org or vger.kernel.org. It is now fixed, so I
> resend this patch for this reason.
>
>  drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
> index 235ce7d..b621fc7 100644
> --- a/drivers/gpu/drm/bridge/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c
> @@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>  	if (intr_stat &
>  	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
>  		mutex_lock(&hdmi->mutex);
> -		if (!hdmi->disabled && !hdmi->force) {
> +		if (!hdmi->force) {
>  			/*
>  			 * If the RX sense status indicates we're disconnected,
>  			 * clear the software rxsense status.

Makes sense but I think you need to make sure that phy will not
be enabled when bridge is disabled i.e. you should update rxsense
only.

Best regards,
Jose Miguel Abreu

[PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Jose Abreu]

Hi Romain,


On 08-03-2017 08:15, Romain Perier wrote:
> Currently, the irq handler that monitores changes for HPD anx RX_SENSE
> relies on the status of the bridge for updating the status of the HPD.
> The update is done only when the bridge is enabled.
>
> However, on Rockchip platforms we have found use cases where it could be
> a problem. When HDMI is being used, turning off/on the screen or
> unplugging/re-plugging the cable, the following simplified code path
> will happen:
>
> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
> hdmi->disabled is false, then the handler will update the rxsense flag
> accordingly.
> - dw_hdmi_update_power() will be invoked with the mode
> DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
> called and the PHY will be desactivated (its pixel clocks and TMDS)
>
> [...]
>
> - dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
> disabled.
>
> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
> currently disabled the HPD status won't be updated, so hdmi->rxsense
> won't be changed. Even if the data part of the PHY is disabled, this
> information coming from the HDMI Transmitter is correct and should be
> saved.
>
> [...]
>
> - dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
> enabled.
> - dw_hdmi_update_power() will be called. As hdmi->force will be equal to
> DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
> field has not been updated by the irq handler, so it will be false and
> DRM_FORCE_ON won't be put to hdmi->force.
>
> Consequently, most of the time dw_hdmi_poweron() won't be called in this
> use case, TMDS won't be re-enabled the PHY won't be re-initialized,
> resulting in a "Signal not found".
>
> This commit fixes the issue by removing the check for "!hdmi->disabled".
> As already explained, even if the PHY is partially disabled, information
> coming from HDMI Transmitter about HPD should be saved for a later use.
>
> Signed-off-by: Romain Perier <romain.perier@collabora.com>
> ---
>
> Note: Due to an email configuration issue, some of my patches were not
> received on infradead.org or vger.kernel.org. It is now fixed, so I
> resend this patch for this reason.
>
>  drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
> index 235ce7d..b621fc7 100644
> --- a/drivers/gpu/drm/bridge/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c
> @@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>  	if (intr_stat &
>  	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
>  		mutex_lock(&hdmi->mutex);
> -		if (!hdmi->disabled && !hdmi->force) {
> +		if (!hdmi->force) {
>  			/*
>  			 * If the RX sense status indicates we're disconnected,
>  			 * clear the software rxsense status.

Makes sense but I think you need to make sure that phy will not
be enabled when bridge is disabled i.e. you should update rxsense
only.

Best regards,
Jose Miguel Abreu

Re: [PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Russell King - ARM Linux]

On Wed, Mar 08, 2017 at 09:15:24AM +0100, Romain Perier wrote:
> - dw_hdmi_update_power() will be called. As hdmi->force will be equal to
> DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
> field has not been updated by the irq handler, so it will be false and
> DRM_FORCE_ON won't be put to hdmi->force.

Right, and wrong.

Your initial part is correct, but the latter sentence is incorrect -
we only ever update hdmi->force according to the user's force requests,
never as a result of the current state of the driver.

hdmi->force exists to allow the user to say "I want to force this connector
to always report disconnected or connected" to work around stupid monitors
that pulse everything from HPD to RXSENSE when in standby mode.

> This commit fixes the issue by removing the check for "!hdmi->disabled".
> As already explained, even if the PHY is partially disabled, information
> coming from HDMI Transmitter about HPD should be saved for a later use.

Your fix looks fine to me, as both dw_hdmi_update_power() and
dw_hdmi_update_phy_mask() effectively ignore attempts to update the
state while hdmi->disabled is true.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

[PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Russell King - ARM Linux]

On Wed, Mar 08, 2017 at 09:15:24AM +0100, Romain Perier wrote:
> - dw_hdmi_update_power() will be called. As hdmi->force will be equal to
> DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
> field has not been updated by the irq handler, so it will be false and
> DRM_FORCE_ON won't be put to hdmi->force.

Right, and wrong.

Your initial part is correct, but the latter sentence is incorrect -
we only ever update hdmi->force according to the user's force requests,
never as a result of the current state of the driver.

hdmi->force exists to allow the user to say "I want to force this connector
to always report disconnected or connected" to work around stupid monitors
that pulse everything from HPD to RXSENSE when in standby mode.

> This commit fixes the issue by removing the check for "!hdmi->disabled".
> As already explained, even if the PHY is partially disabled, information
> coming from HDMI Transmitter about HPD should be saved for a later use.

Your fix looks fine to me, as both dw_hdmi_update_power() and
dw_hdmi_update_phy_mask() effectively ignore attempts to update the
state while hdmi->disabled is true.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

Re: [PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Romain Perier]

Hello,


Le 09/03/2017 à 15:28, Jose Abreu a écrit :
> Hi Romain,
>
>
> On 08-03-2017 08:15, Romain Perier wrote:
>> Currently, the irq handler that monitores changes for HPD anx RX_SENSE
>> relies on the status of the bridge for updating the status of the HPD.
>> The update is done only when the bridge is enabled.
>>
>> However, on Rockchip platforms we have found use cases where it could be
>> a problem. When HDMI is being used, turning off/on the screen or
>> unplugging/re-plugging the cable, the following simplified code path
>> will happen:
>>
>> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
>> hdmi->disabled is false, then the handler will update the rxsense flag
>> accordingly.
>> - dw_hdmi_update_power() will be invoked with the mode
>> DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
>> called and the PHY will be desactivated (its pixel clocks and TMDS)
>>
>> [...]
>>
>> - dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
>> disabled.
>>
>> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
>> currently disabled the HPD status won't be updated, so hdmi->rxsense
>> won't be changed. Even if the data part of the PHY is disabled, this
>> information coming from the HDMI Transmitter is correct and should be
>> saved.
>>
>> [...]
>>
>> - dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
>> enabled.
>> - dw_hdmi_update_power() will be called. As hdmi->force will be equal to
>> DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
>> field has not been updated by the irq handler, so it will be false and
>> DRM_FORCE_ON won't be put to hdmi->force.
>>
>> Consequently, most of the time dw_hdmi_poweron() won't be called in this
>> use case, TMDS won't be re-enabled the PHY won't be re-initialized,
>> resulting in a "Signal not found".
>>
>> This commit fixes the issue by removing the check for "!hdmi->disabled".
>> As already explained, even if the PHY is partially disabled, information
>> coming from HDMI Transmitter about HPD should be saved for a later use.
>>
>> Signed-off-by: Romain Perier <romain.perier@collabora.com>
>> ---
>>
>> Note: Due to an email configuration issue, some of my patches were not
>> received on infradead.org or vger.kernel.org. It is now fixed, so I
>> resend this patch for this reason.
>>
>>  drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
>> index 235ce7d..b621fc7 100644
>> --- a/drivers/gpu/drm/bridge/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c
>> @@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>>  	if (intr_stat &
>>  	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
>>  		mutex_lock(&hdmi->mutex);
>> -		if (!hdmi->disabled && !hdmi->force) {
>> +		if (!hdmi->force) {
>>  			/*
>>  			 * If the RX sense status indicates we're disconnected,
>>  			 * clear the software rxsense status.
> Makes sense but I think you need to make sure that phy will not
> be enabled when bridge is disabled i.e. you should update rxsense
> only.
>
> Best regards,
> Jose Miguel Abreu
I agree with Russel, dw_hdmi_update_phy_mask already checks that. So it
should not be enabled, imho.

Regards,
Romain

Re: [PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Romain Perier]

Hello,


Le 09/03/2017 à 15:28, Jose Abreu a écrit :
> Hi Romain,
>
>
> On 08-03-2017 08:15, Romain Perier wrote:
>> Currently, the irq handler that monitores changes for HPD anx RX_SENSE
>> relies on the status of the bridge for updating the status of the HPD.
>> The update is done only when the bridge is enabled.
>>
>> However, on Rockchip platforms we have found use cases where it could be
>> a problem. When HDMI is being used, turning off/on the screen or
>> unplugging/re-plugging the cable, the following simplified code path
>> will happen:
>>
>> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
>> hdmi->disabled is false, then the handler will update the rxsense flag
>> accordingly.
>> - dw_hdmi_update_power() will be invoked with the mode
>> DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
>> called and the PHY will be desactivated (its pixel clocks and TMDS)
>>
>> [...]
>>
>> - dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
>> disabled.
>>
>> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
>> currently disabled the HPD status won't be updated, so hdmi->rxsense
>> won't be changed. Even if the data part of the PHY is disabled, this
>> information coming from the HDMI Transmitter is correct and should be
>> saved.
>>
>> [...]
>>
>> - dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
>> enabled.
>> - dw_hdmi_update_power() will be called. As hdmi->force will be equal to
>> DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
>> field has not been updated by the irq handler, so it will be false and
>> DRM_FORCE_ON won't be put to hdmi->force.
>>
>> Consequently, most of the time dw_hdmi_poweron() won't be called in this
>> use case, TMDS won't be re-enabled the PHY won't be re-initialized,
>> resulting in a "Signal not found".
>>
>> This commit fixes the issue by removing the check for "!hdmi->disabled".
>> As already explained, even if the PHY is partially disabled, information
>> coming from HDMI Transmitter about HPD should be saved for a later use.
>>
>> Signed-off-by: Romain Perier <romain.perier@collabora.com>
>> ---
>>
>> Note: Due to an email configuration issue, some of my patches were not
>> received on infradead.org or vger.kernel.org. It is now fixed, so I
>> resend this patch for this reason.
>>
>>  drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
>> index 235ce7d..b621fc7 100644
>> --- a/drivers/gpu/drm/bridge/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c
>> @@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>>  	if (intr_stat &
>>  	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
>>  		mutex_lock(&hdmi->mutex);
>> -		if (!hdmi->disabled && !hdmi->force) {
>> +		if (!hdmi->force) {
>>  			/*
>>  			 * If the RX sense status indicates we're disconnected,
>>  			 * clear the software rxsense status.
> Makes sense but I think you need to make sure that phy will not
> be enabled when bridge is disabled i.e. you should update rxsense
> only.
>
> Best regards,
> Jose Miguel Abreu
I agree with Russel, dw_hdmi_update_phy_mask already checks that. So it
should not be enabled, imho.

Regards,
Romain

[PATCH RESEND] drm: dw_hdmi: Don't rely on the status of the bridge for updating HPD

[Romain Perier]

Hello,


Le 09/03/2017 ? 15:28, Jose Abreu a ?crit :
> Hi Romain,
>
>
> On 08-03-2017 08:15, Romain Perier wrote:
>> Currently, the irq handler that monitores changes for HPD anx RX_SENSE
>> relies on the status of the bridge for updating the status of the HPD.
>> The update is done only when the bridge is enabled.
>>
>> However, on Rockchip platforms we have found use cases where it could be
>> a problem. When HDMI is being used, turning off/on the screen or
>> unplugging/re-plugging the cable, the following simplified code path
>> will happen:
>>
>> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is on
>> hdmi->disabled is false, then the handler will update the rxsense flag
>> accordingly.
>> - dw_hdmi_update_power() will be invoked with the mode
>> DRM_FORCE_UNSPECIFIED and rxsense == 1, so dw_hdmi_poweroff() will be
>> called and the PHY will be desactivated (its pixel clocks and TMDS)
>>
>> [...]
>>
>> - dw_hdmi_bridge_disable() will be invoked, the bridge will be marked as
>> disabled.
>>
>> - dw_hdmi_irq() will be triggered by an HPD event, as the bridge is
>> currently disabled the HPD status won't be updated, so hdmi->rxsense
>> won't be changed. Even if the data part of the PHY is disabled, this
>> information coming from the HDMI Transmitter is correct and should be
>> saved.
>>
>> [...]
>>
>> - dw_hdmi_bridge_enable() will be invoked, the bridge will be marked as
>> enabled.
>> - dw_hdmi_update_power() will be called. As hdmi->force will be equal to
>> DRM_FORCE_UNSPECIFIED the function will rely on hdmi->rxsense. This
>> field has not been updated by the irq handler, so it will be false and
>> DRM_FORCE_ON won't be put to hdmi->force.
>>
>> Consequently, most of the time dw_hdmi_poweron() won't be called in this
>> use case, TMDS won't be re-enabled the PHY won't be re-initialized,
>> resulting in a "Signal not found".
>>
>> This commit fixes the issue by removing the check for "!hdmi->disabled".
>> As already explained, even if the PHY is partially disabled, information
>> coming from HDMI Transmitter about HPD should be saved for a later use.
>>
>> Signed-off-by: Romain Perier <romain.perier@collabora.com>
>> ---
>>
>> Note: Due to an email configuration issue, some of my patches were not
>> received on infradead.org or vger.kernel.org. It is now fixed, so I
>> resend this patch for this reason.
>>
>>  drivers/gpu/drm/bridge/dw-hdmi.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/dw-hdmi.c b/drivers/gpu/drm/bridge/dw-hdmi.c
>> index 235ce7d..b621fc7 100644
>> --- a/drivers/gpu/drm/bridge/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/dw-hdmi.c
>> @@ -1790,7 +1790,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id)
>>  	if (intr_stat &
>>  	    (HDMI_IH_PHY_STAT0_RX_SENSE | HDMI_IH_PHY_STAT0_HPD)) {
>>  		mutex_lock(&hdmi->mutex);
>> -		if (!hdmi->disabled && !hdmi->force) {
>> +		if (!hdmi->force) {
>>  			/*
>>  			 * If the RX sense status indicates we're disconnected,
>>  			 * clear the software rxsense status.
> Makes sense but I think you need to make sure that phy will not
> be enabled when bridge is disabled i.e. you should update rxsense
> only.
>
> Best regards,
> Jose Miguel Abreu
I agree with Russel, dw_hdmi_update_phy_mask already checks that. So it
should not be enabled, imho.

Regards,
Romain