[PATCH] drm/dp: add a hw mutex around the transfer functions.

[Dave Airlie]

From: Dave Airlie 

This should avoid races between connector probing and HPD
irqs in the future, currently mode_config.mutex blocks this
possibility.

Signed-off-by: Dave Airlie 
---
 drivers/gpu/drm/drm_dp_helper.c  | 15 +++
 drivers/gpu/drm/i915/intel_dp.c  |  1 +
 drivers/gpu/drm/radeon/atombios_dp.c |  2 ++
 drivers/gpu/drm/tegra/dpaux.c|  1 +
 include/drm/drm_dp_helper.h  |  3 ++-
 5 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 494219c..cb687f4 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -382,7 +382,10 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 
request,
 * transactions.
 */
for (retry = 0; retry < 7; retry++) {
+
+   mutex_lock(>hw_mutex);
err = aux->transfer(aux, );
+   mutex_unlock(>hw_mutex);
if (err < 0) {
if (err == -EBUSY)
continue;
@@ -596,7 +599,9 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct 
drm_dp_aux_msg *msg)
 * before giving up the AUX transaction.
 */
for (retry = 0; retry < 7; retry++) {
+   mutex_lock(>hw_mutex);
err = aux->transfer(aux, msg);
+   mutex_unlock(>hw_mutex);
if (err < 0) {
if (err == -EBUSY)
continue;
@@ -761,3 +766,13 @@ void drm_dp_aux_unregister_i2c_bus(struct drm_dp_aux *aux)
i2c_del_adapter(>ddc);
 }
 EXPORT_SYMBOL(drm_dp_aux_unregister_i2c_bus);
+
+/**
+ * drm_dp_aux_init() - init a DP aux internal structure.
+ * @aux: DisplayPort AUX channel
+ */
+void drm_dp_aux_init(struct drm_dp_aux *aux)
+{
+   mutex_init(>hw_mutex);
+}
+EXPORT_SYMBOL(drm_dp_aux_init);
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c4d8839..aa99dcb 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -698,6 +698,7 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct 
intel_connector *connector)
intel_dp->aux.name = name;
intel_dp->aux.dev = dev->dev;
intel_dp->aux.transfer = intel_dp_aux_transfer;
+   drm_dp_aux_init(_dp->aux);

DRM_DEBUG_KMS("registering %s bus for %s\n", name,
  connector->base.kdev->kobj.name);
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c 
b/drivers/gpu/drm/radeon/atombios_dp.c
index 225f6c6..12d8784 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -222,6 +222,8 @@ void radeon_dp_aux_init(struct radeon_connector 
*radeon_connector)
radeon_connector->ddc_bus->rec.hpd = radeon_connector->hpd.hpd;
radeon_connector->ddc_bus->aux.dev = radeon_connector->base.kdev;
radeon_connector->ddc_bus->aux.transfer = radeon_dp_aux_transfer;
+
+   drm_dp_aux_init(_connector->ddc_bus->aux);
ret = drm_dp_aux_register_i2c_bus(_connector->ddc_bus->aux);
if (!ret)
radeon_connector->ddc_bus->has_aux = true;
diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index 005c19b..98cd70b 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -331,6 +331,7 @@ static int tegra_dpaux_probe(struct platform_device *pdev)

dpaux->aux.transfer = tegra_dpaux_transfer;
dpaux->aux.dev = >dev;
+   drm_dp_aux_init(>aux);

err = drm_dp_aux_register_i2c_bus(>aux);
if (err < 0)
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 488b416..09eee36 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -546,7 +546,7 @@ struct drm_dp_aux {
const char *name;
struct i2c_adapter ddc;
struct device *dev;
-
+   struct mutex hw_mutex;
ssize_t (*transfer)(struct drm_dp_aux *aux,
struct drm_dp_aux_msg *msg);
 };
@@ -607,5 +607,6 @@ int drm_dp_link_configure(struct drm_dp_aux *aux, struct 
drm_dp_link *link);

 int drm_dp_aux_register_i2c_bus(struct drm_dp_aux *aux);
 void drm_dp_aux_unregister_i2c_bus(struct drm_dp_aux *aux);
+void drm_dp_aux_init(struct drm_dp_aux *aux);

 #endif /* _DRM_DP_HELPER_H_ */
-- 
1.9.3

[PATCH] drm/dp: add a hw mutex around the transfer functions.

[Daniel Vetter]

On Wed, Jun 04, 2014 at 04:04:25PM +1000, Dave Airlie wrote:
> From: Dave Airlie 
> 
> This should avoid races between connector probing and HPD
> irqs in the future, currently mode_config.mutex blocks this
> possibility.
> 
> Signed-off-by: Dave Airlie 
> ---
>  drivers/gpu/drm/drm_dp_helper.c  | 15 +++
>  drivers/gpu/drm/i915/intel_dp.c  |  1 +
>  drivers/gpu/drm/radeon/atombios_dp.c |  2 ++
>  drivers/gpu/drm/tegra/dpaux.c|  1 +
>  include/drm/drm_dp_helper.h  |  3 ++-
>  5 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 494219c..cb687f4 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -382,7 +382,10 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 
> request,
>* transactions.
>*/
>   for (retry = 0; retry < 7; retry++) {
> +
> + mutex_lock(>hw_mutex);
>   err = aux->transfer(aux, );
> + mutex_unlock(>hw_mutex);
>   if (err < 0) {
>   if (err == -EBUSY)
>   continue;
> @@ -596,7 +599,9 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, 
> struct drm_dp_aux_msg *msg)
>* before giving up the AUX transaction.
>*/
>   for (retry = 0; retry < 7; retry++) {
> + mutex_lock(>hw_mutex);
>   err = aux->transfer(aux, msg);
> + mutex_unlock(>hw_mutex);
>   if (err < 0) {
>   if (err == -EBUSY)
>   continue;
> @@ -761,3 +766,13 @@ void drm_dp_aux_unregister_i2c_bus(struct drm_dp_aux 
> *aux)
>   i2c_del_adapter(>ddc);
>  }
>  EXPORT_SYMBOL(drm_dp_aux_unregister_i2c_bus);
> +
> +/**
> + * drm_dp_aux_init() - init a DP aux internal structure.
> + * @aux: DisplayPort AUX channel
> + */
> +void drm_dp_aux_init(struct drm_dp_aux *aux)
> +{
> + mutex_init(>hw_mutex);
> +}

Imo we should merge this with drm_dp_aux_register (and drop the i2c_bus
part of it since it'll be more generic) - no driver should call one
without the other.

With that address this is Reviewed-by: Daniel Vetter 

> +EXPORT_SYMBOL(drm_dp_aux_init);
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index c4d8839..aa99dcb 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -698,6 +698,7 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct 
> intel_connector *connector)
>   intel_dp->aux.name = name;
>   intel_dp->aux.dev = dev->dev;
>   intel_dp->aux.transfer = intel_dp_aux_transfer;
> + drm_dp_aux_init(_dp->aux);
>  
>   DRM_DEBUG_KMS("registering %s bus for %s\n", name,
> connector->base.kdev->kobj.name);
> diff --git a/drivers/gpu/drm/radeon/atombios_dp.c 
> b/drivers/gpu/drm/radeon/atombios_dp.c
> index 225f6c6..12d8784 100644
> --- a/drivers/gpu/drm/radeon/atombios_dp.c
> +++ b/drivers/gpu/drm/radeon/atombios_dp.c
> @@ -222,6 +222,8 @@ void radeon_dp_aux_init(struct radeon_connector 
> *radeon_connector)
>   radeon_connector->ddc_bus->rec.hpd = radeon_connector->hpd.hpd;
>   radeon_connector->ddc_bus->aux.dev = radeon_connector->base.kdev;
>   radeon_connector->ddc_bus->aux.transfer = radeon_dp_aux_transfer;
> +
> + drm_dp_aux_init(_connector->ddc_bus->aux);
>   ret = drm_dp_aux_register_i2c_bus(_connector->ddc_bus->aux);
>   if (!ret)
>   radeon_connector->ddc_bus->has_aux = true;
> diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
> index 005c19b..98cd70b 100644
> --- a/drivers/gpu/drm/tegra/dpaux.c
> +++ b/drivers/gpu/drm/tegra/dpaux.c
> @@ -331,6 +331,7 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
>  
>   dpaux->aux.transfer = tegra_dpaux_transfer;
>   dpaux->aux.dev = >dev;
> + drm_dp_aux_init(>aux);
>  
>   err = drm_dp_aux_register_i2c_bus(>aux);
>   if (err < 0)
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 488b416..09eee36 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -546,7 +546,7 @@ struct drm_dp_aux {
>   const char *name;
>   struct i2c_adapter ddc;
>   struct device *dev;
> -
> + struct mutex hw_mutex;
>   ssize_t (*transfer)(struct drm_dp_aux *aux,
>   struct drm_dp_aux_msg *msg);
>  };
> @@ -607,5 +607,6 @@ int drm_dp_link_configure(struct drm_dp_aux *aux, struct 
> drm_dp_link *link);
>  
>  int drm_dp_aux_register_i2c_bus(struct drm_dp_aux *aux);
>  void drm_dp_aux_unregister_i2c_bus(struct drm_dp_aux *aux);
> +void drm_dp_aux_init(struct drm_dp_aux *aux);
>  
>  #endif /* _DRM_DP_HELPER_H_ */
> -- 
> 1.9.3
> 
> ___
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel