diff options
| -rw-r--r-- | drivers/gpu/drm/drm_dp_mst_topology.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 229ad6026314..f0cbd5fad8fc 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3250,6 +3250,23 @@ void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr) } EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy); +static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num) +{ + int i; + + if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS) + return false; + + for (i = 0; i < num - 1; i++) { + if (msgs[i].flags & I2C_M_RD || + msgs[i].len > 0xff) + return false; + } + + return msgs[num - 1].flags & I2C_M_RD && + msgs[num - 1].len <= 0xff; +} + /* I2C device */ static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) @@ -3259,7 +3276,6 @@ static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs struct drm_dp_mst_branch *mstb; struct drm_dp_mst_topology_mgr *mgr = port->mgr; unsigned int i; - bool reading = false; struct drm_dp_sideband_msg_req_body msg; struct drm_dp_sideband_msg_tx *txmsg = NULL; int ret; @@ -3268,12 +3284,7 @@ static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs if (!mstb) return -EREMOTEIO; - /* construct i2c msg */ - /* see if last msg is a read */ - if (msgs[num - 1].flags & I2C_M_RD) - reading = true; - - if (!reading || (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)) { + if (!remote_i2c_read_ok(msgs, num)) { DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n"); ret = -EIO; goto out; |