From 953b921688bb14675ebdf3c36148d5a6cd7e1a76 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 3 Jun 2024 07:09:00 +0200 Subject: Merging upstream version 6.8.12. Signed-off-by: Daniel Baumann --- drivers/gpu/drm/display/drm_dp_helper.c | 35 +++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'drivers/gpu/drm/display') diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c index 26c188ce5f..fb80843e7f 100644 --- a/drivers/gpu/drm/display/drm_dp_helper.c +++ b/drivers/gpu/drm/display/drm_dp_helper.c @@ -532,6 +532,15 @@ 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 @@ -599,6 +608,29 @@ 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) @@ -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)); -- cgit v1.2.3