Needed for proper i2c over aux handling for certain monitors and configurations (e.g., dp bridges or adapters).
Signed-off-by: Alex Deucher alexander.deucher@amd.com --- drivers/gpu/drm/radeon/atombios_dp.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index 8b0ab17..f143128 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -143,6 +143,7 @@ static int radeon_process_aux_ch(struct radeon_i2c_chan *chan, }
#define HEADER_SIZE 4 +#define BARE_ADDRESS_SIZE 3
static ssize_t radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) @@ -165,8 +166,12 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) switch (msg->request & ~DP_AUX_I2C_MOT) { case DP_AUX_NATIVE_WRITE: case DP_AUX_I2C_WRITE: + /* handle bare */ tx_size = HEADER_SIZE + msg->size; - tx_buf[3] |= tx_size << 4; + if (msg->flags & DRM_DP_AUX_MSG_FLAGS_BARE_ADDRESS) + tx_buf[3] |= BARE_ADDRESS_SIZE << 4; + else + tx_buf[3] |= tx_size << 4; memcpy(tx_buf + HEADER_SIZE, msg->buffer, msg->size); ret = radeon_process_aux_ch(chan, tx_buf, tx_size, NULL, 0, delay, &ack); @@ -177,9 +182,15 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) case DP_AUX_NATIVE_READ: case DP_AUX_I2C_READ: tx_size = HEADER_SIZE; - tx_buf[3] |= tx_size << 4; + if (msg->flags & DRM_DP_AUX_MSG_FLAGS_BARE_ADDRESS) + tx_buf[3] |= BARE_ADDRESS_SIZE << 4; + else + tx_buf[3] |= tx_size << 4; ret = radeon_process_aux_ch(chan, tx_buf, tx_size, msg->buffer, msg->size, delay, &ack); + /* sending just the address transfers 0 bytes */ + if ((msg->flags & DRM_DP_AUX_MSG_FLAGS_BARE_ADDRESS) && (ret == 0)) + ret++; break; default: ret = -EINVAL;