@@ -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)
@@ -160,13 +161,16 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
tx_buf[0] = msg->address & 0xff;
tx_buf[1] = msg->address >> 8;
tx_buf[2] = msg->request << 4;
- tx_buf[3] = msg->size - 1;
+ tx_buf[3] = msg->size ? (msg->size - 1) : 0;
switch (msg->request & ~DP_AUX_I2C_MOT) {
case DP_AUX_NATIVE_WRITE:
case DP_AUX_I2C_WRITE:
tx_size = HEADER_SIZE + msg->size;
- tx_buf[3] |= tx_size << 4;
+ if (msg->size == 0)
+ 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);
@@ -177,7 +181,10 @@ 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->size == 0)
+ 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);
break;
@@ -186,7 +193,7 @@ radeon_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
break;
}
- if (ret > 0)
+ if (ret >= 0)
msg->reply = ack >> 4;
return ret;
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, 11 insertions(+), 4 deletions(-)