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(-)
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index 8b0ab17..e914008 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) @@ -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;