diff options
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_helper.c | 35 | ||||
| -rw-r--r-- | drivers/gpu/drm/panel/panel-edp.c | 3 | ||||
| -rw-r--r-- | drivers/gpu/drm/panel/panel-samsung-atna33xc20.c | 2 | ||||
| -rw-r--r-- | include/drm/display/drm_dp_helper.h | 6 |
4 files changed, 46 insertions, 0 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c index 9ac52cf5d4d8..57a32e962322 100644 --- a/drivers/gpu/drm/display/drm_dp_helper.c +++ b/drivers/gpu/drm/display/drm_dp_helper.c @@ -533,6 +533,15 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, mutex_lock(&aux->hw_mutex); /* + * If the device attached to the aux bus is powered down then there's + * no reason to attempt a transfer. Error out immediately. + */ + if (aux->powered_down) { + ret = -EBUSY; + goto unlock; + } + + /* * The specification doesn't give any recommendation on how often to * retry native transactions. We used to retry 7 times like for * aux i2c transactions but real world devices this wasn't @@ -600,6 +609,29 @@ int drm_dp_dpcd_probe(struct drm_dp_aux *aux, unsigned int offset) EXPORT_SYMBOL(drm_dp_dpcd_probe); /** + * drm_dp_dpcd_set_powered() - Set whether the DP device is powered + * @aux: DisplayPort AUX channel; for convenience it's OK to pass NULL here + * and the function will be a no-op. + * @powered: true if powered; false if not + * + * If the endpoint device on the DP AUX bus is known to be powered down + * then this function can be called to make future transfers fail immediately + * instead of needing to time out. + * + * If this function is never called then a device defaults to being powered. + */ +void drm_dp_dpcd_set_powered(struct drm_dp_aux *aux, bool powered) +{ + if (!aux) + return; + + mutex_lock(&aux->hw_mutex); + aux->powered_down = !powered; + mutex_unlock(&aux->hw_mutex); +} +EXPORT_SYMBOL(drm_dp_dpcd_set_powered); + +/** * drm_dp_dpcd_read() - read a series of bytes from the DPCD * @aux: DisplayPort AUX channel (SST or MST) * @offset: address of the (first) register to read @@ -1858,6 +1890,9 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, struct drm_dp_aux_msg msg; int err = 0; + if (aux->powered_down) + return -EBUSY; + dp_aux_i2c_transfer_size = clamp(dp_aux_i2c_transfer_size, 1, DP_AUX_MAX_PAYLOAD_BYTES); memset(&msg, 0, sizeof(msg)); diff --git a/drivers/gpu/drm/panel/panel-edp.c b/drivers/gpu/drm/panel/panel-edp.c index bd71d239272a..d58f90bc48fb 100644 --- a/drivers/gpu/drm/panel/panel-edp.c +++ b/drivers/gpu/drm/panel/panel-edp.c @@ -413,6 +413,7 @@ static int panel_edp_suspend(struct device *dev) { struct panel_edp *p = dev_get_drvdata(dev); + drm_dp_dpcd_set_powered(p->aux, false); gpiod_set_value_cansleep(p->enable_gpio, 0); regulator_disable(p->supply); p->unprepared_time = ktime_get_boottime(); @@ -469,6 +470,7 @@ static int panel_edp_prepare_once(struct panel_edp *p) } gpiod_set_value_cansleep(p->enable_gpio, 1); + drm_dp_dpcd_set_powered(p->aux, true); p->powered_on_time = ktime_get_boottime(); @@ -507,6 +509,7 @@ static int panel_edp_prepare_once(struct panel_edp *p) return 0; error: + drm_dp_dpcd_set_powered(p->aux, false); gpiod_set_value_cansleep(p->enable_gpio, 0); regulator_disable(p->supply); p->unprepared_time = ktime_get_boottime(); diff --git a/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c b/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c index 5703f4712d96..76c2a8f6718c 100644 --- a/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c +++ b/drivers/gpu/drm/panel/panel-samsung-atna33xc20.c @@ -72,6 +72,7 @@ static int atana33xc20_suspend(struct device *dev) if (p->el3_was_on) atana33xc20_wait(p->el_on3_off_time, 150); + drm_dp_dpcd_set_powered(p->aux, false); ret = regulator_disable(p->supply); if (ret) return ret; @@ -93,6 +94,7 @@ static int atana33xc20_resume(struct device *dev) ret = regulator_enable(p->supply); if (ret) return ret; + drm_dp_dpcd_set_powered(p->aux, true); p->powered_on_time = ktime_get_boottime(); if (p->no_hpd) { diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h index 0c1a4021e098..4cf6cb3797ad 100644 --- a/include/drm/display/drm_dp_helper.h +++ b/include/drm/display/drm_dp_helper.h @@ -464,9 +464,15 @@ struct drm_dp_aux { * @is_remote: Is this AUX CH actually using sideband messaging. */ bool is_remote; + + /** + * @powered_down: If true then the remote endpoint is powered down. + */ + bool powered_down; }; int drm_dp_dpcd_probe(struct drm_dp_aux *aux, unsigned int offset); +void drm_dp_dpcd_set_powered(struct drm_dp_aux *aux, bool powered); ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset, void *buffer, size_t size); ssize_t drm_dp_dpcd_write(struct drm_dp_aux *aux, unsigned int offset, |