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drm/dp: add a hw mutex around the transfer functions. (v2)
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This should avoid races between connector probing and HPD
irqs in the future, currently mode_config.mutex blocks this
possibility.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
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Dave Airlie committed Jun 4, 2014
1 parent 885ae1c commit 4f71d0c
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Showing 6 changed files with 29 additions and 20 deletions.
21 changes: 14 additions & 7 deletions drivers/gpu/drm/drm_dp_helper.c
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Original file line number Diff line number Diff line change
Expand Up @@ -216,7 +216,7 @@ i2c_dp_aux_prepare_bus(struct i2c_adapter *adapter)
*
* IMPORTANT:
* This interface is deprecated, please switch to the new dp aux helpers and
* drm_dp_aux_register_i2c_bus().
* drm_dp_aux_register().
*/
int
i2c_dp_aux_add_bus(struct i2c_adapter *adapter)
Expand Down Expand Up @@ -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(&aux->hw_mutex);
err = aux->transfer(aux, &msg);
mutex_unlock(&aux->hw_mutex);
if (err < 0) {
if (err == -EBUSY)
continue;
Expand Down Expand Up @@ -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(&aux->hw_mutex);
err = aux->transfer(aux, msg);
mutex_unlock(&aux->hw_mutex);
if (err < 0) {
if (err == -EBUSY)
continue;
Expand Down Expand Up @@ -729,13 +734,15 @@ static const struct i2c_algorithm drm_dp_i2c_algo = {
};

/**
* drm_dp_aux_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
* drm_dp_aux_register() - initialise and register aux channel
* @aux: DisplayPort AUX channel
*
* Returns 0 on success or a negative error code on failure.
*/
int drm_dp_aux_register_i2c_bus(struct drm_dp_aux *aux)
int drm_dp_aux_register(struct drm_dp_aux *aux)
{
mutex_init(&aux->hw_mutex);

aux->ddc.algo = &drm_dp_i2c_algo;
aux->ddc.algo_data = aux;
aux->ddc.retries = 3;
Expand All @@ -750,14 +757,14 @@ int drm_dp_aux_register_i2c_bus(struct drm_dp_aux *aux)

return i2c_add_adapter(&aux->ddc);
}
EXPORT_SYMBOL(drm_dp_aux_register_i2c_bus);
EXPORT_SYMBOL(drm_dp_aux_register);

/**
* drm_dp_aux_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
* drm_dp_aux_unregister() - unregister an AUX adapter
* @aux: DisplayPort AUX channel
*/
void drm_dp_aux_unregister_i2c_bus(struct drm_dp_aux *aux)
void drm_dp_aux_unregister(struct drm_dp_aux *aux)
{
i2c_del_adapter(&aux->ddc);
}
EXPORT_SYMBOL(drm_dp_aux_unregister_i2c_bus);
EXPORT_SYMBOL(drm_dp_aux_unregister);
10 changes: 5 additions & 5 deletions drivers/gpu/drm/i915/intel_dp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -702,9 +702,9 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
DRM_DEBUG_KMS("registering %s bus for %s\n", name,
connector->base.kdev->kobj.name);

ret = drm_dp_aux_register_i2c_bus(&intel_dp->aux);
ret = drm_dp_aux_register(&intel_dp->aux);
if (ret < 0) {
DRM_ERROR("drm_dp_aux_register_i2c_bus() for %s failed (%d)\n",
DRM_ERROR("drm_dp_aux_register() for %s failed (%d)\n",
name, ret);
return;
}
Expand All @@ -714,7 +714,7 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
intel_dp->aux.ddc.dev.kobj.name);
if (ret < 0) {
DRM_ERROR("sysfs_create_link() for %s failed (%d)\n", name, ret);
drm_dp_aux_unregister_i2c_bus(&intel_dp->aux);
drm_dp_aux_unregister(&intel_dp->aux);
}
}

Expand Down Expand Up @@ -3662,7 +3662,7 @@ void intel_dp_encoder_destroy(struct drm_encoder *encoder)
struct intel_dp *intel_dp = &intel_dig_port->dp;
struct drm_device *dev = intel_dp_to_dev(intel_dp);

drm_dp_aux_unregister_i2c_bus(&intel_dp->aux);
drm_dp_aux_unregister(&intel_dp->aux);
drm_encoder_cleanup(encoder);
if (is_edp(intel_dp)) {
cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
Expand Down Expand Up @@ -4244,7 +4244,7 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
intel_dp->psr_setup_done = false;

if (!intel_edp_init_connector(intel_dp, intel_connector, &power_seq)) {
drm_dp_aux_unregister_i2c_bus(&intel_dp->aux);
drm_dp_aux_unregister(&intel_dp->aux);
if (is_edp(intel_dp)) {
cancel_delayed_work_sync(&intel_dp->panel_vdd_work);
mutex_lock(&dev->mode_config.connection_mutex);
Expand Down
5 changes: 3 additions & 2 deletions drivers/gpu/drm/radeon/atombios_dp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -222,11 +222,12 @@ 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;
ret = drm_dp_aux_register_i2c_bus(&radeon_connector->ddc_bus->aux);

ret = drm_dp_aux_register(&radeon_connector->ddc_bus->aux);
if (!ret)
radeon_connector->ddc_bus->has_aux = true;

WARN(ret, "drm_dp_aux_register_i2c_bus() failed with error %d\n", ret);
WARN(ret, "drm_dp_aux_register() failed with error %d\n", ret);
}

/***** general DP utility functions *****/
Expand Down
2 changes: 1 addition & 1 deletion drivers/gpu/drm/radeon/radeon_i2c.c
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Original file line number Diff line number Diff line change
Expand Up @@ -988,7 +988,7 @@ void radeon_i2c_destroy(struct radeon_i2c_chan *i2c)
return;
i2c_del_adapter(&i2c->adapter);
if (i2c->has_aux)
drm_dp_aux_unregister_i2c_bus(&i2c->aux);
drm_dp_aux_unregister(&i2c->aux);
kfree(i2c);
}

Expand Down
4 changes: 2 additions & 2 deletions drivers/gpu/drm/tegra/dpaux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -332,7 +332,7 @@ static int tegra_dpaux_probe(struct platform_device *pdev)
dpaux->aux.transfer = tegra_dpaux_transfer;
dpaux->aux.dev = &pdev->dev;

err = drm_dp_aux_register_i2c_bus(&dpaux->aux);
err = drm_dp_aux_register(&dpaux->aux);
if (err < 0)
return err;

Expand All @@ -355,7 +355,7 @@ static int tegra_dpaux_remove(struct platform_device *pdev)
{
struct tegra_dpaux *dpaux = platform_get_drvdata(pdev);

drm_dp_aux_unregister_i2c_bus(&dpaux->aux);
drm_dp_aux_unregister(&dpaux->aux);

mutex_lock(&dpaux_lock);
list_del(&dpaux->list);
Expand Down
7 changes: 4 additions & 3 deletions include/drm/drm_dp_helper.h
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Original file line number Diff line number Diff line change
Expand Up @@ -514,6 +514,7 @@ struct drm_dp_aux_msg {
* @name: user-visible name of this AUX channel and the I2C-over-AUX adapter
* @ddc: I2C adapter that can be used for I2C-over-AUX communication
* @dev: pointer to struct device that is the parent for this AUX channel
* @hw_mutex: internal mutex used for locking transfers
* @transfer: transfers a message representing a single AUX transaction
*
* The .dev field should be set to a pointer to the device that implements
Expand Down Expand Up @@ -546,7 +547,7 @@ 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);
};
Expand Down Expand Up @@ -605,7 +606,7 @@ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link);
int drm_dp_link_power_up(struct drm_dp_aux *aux, struct drm_dp_link *link);
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);
int drm_dp_aux_register(struct drm_dp_aux *aux);
void drm_dp_aux_unregister(struct drm_dp_aux *aux);

#endif /* _DRM_DP_HELPER_H_ */

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