Attachment 118905 Details for Bug 92481 – Numerous mostly cosmetic fixed to drm_dp_mst_i2c_xfer in linux 4.3-rc5/drivers/gpu/drm/drm_dp_mst_topology.c AFTER Dave Airlie's other changes have been applied

Numerous mostly cosmetic fixed to drm_dp_mst_i2c_xfer in linux 4.3-rc5/drivers/gpu/drm/drm_dp_mst_topology.c AFTER Dave Airlie's other changes have been applied

drm_dp_mst_i2c_xfer.mostly_cosmetic_fixes.diff (text/plain), 3.15 KB, created by Adam J. Richter on 2015-10-15 21:27:28 UTC

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Creator: Adam J. Richter

Created: 2015-10-15 21:27:28 UTC

Size: 3.15 KB

patch

obsolete

>--- linux-4.3.0-rc5/drivers/gpu/drm/drm_dp_mst_topology.c.old	2015-10-15 00:52:13.293418345 -0700
>+++ linux-4.3.0-rc5/drivers/gpu/drm/drm_dp_mst_topology.c	2015-10-15 00:53:32.145852512 -0700
>@@ -2780,48 +2780,55 @@ void drm_dp_mst_topology_mgr_destroy(str
> EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
> 
> /* I2C device */
>-static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
>+static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
>+			       struct i2c_msg *msgs,
> 			       int num)
> {
> 	struct drm_dp_aux *aux = adapter->algo_data;
>-	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
>+	struct drm_dp_mst_port *port =
>+		container_of(aux, struct drm_dp_mst_port, aux);
> 	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;
>+	struct drm_dp_sideband_msg_tx *txmsg;
> 	int ret;
>+	int count;
> 
>-	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
>-	if (!mstb)
>-		return -EREMOTEIO;
>+	if (unlikely(num <= 0)) {
>+		DRM_DEBUG_KMS("Too few DP-MST I2C transactions (%d).\n", num);
>+		return -EDOM;
>+	}
> 
>-	/* 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)) {
>-		DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
>-		ret = -EIO;
>-		goto out;
>+	if (unlikely(num > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS + 1)) {
>+		DRM_DEBUG_KMS("Too many DP-MST I2C transactions (%d).\n", num);
>+		return -E2BIG;
> 	}
> 
>+	count = num - 1;
>+	if (!likely(msgs[count].flags & I2C_M_RD)) {
>+		DRM_DEBUG_KMS("Final DP-MST I2C transaction was not a read.\n");
>+		return -EINVAL;
>+	}
>+
>+	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
>+	if (unlikely(!mstb))
>+		return -EREMOTEIO;
>+
> 	memset(&msg, 0, sizeof(msg));
> 	msg.req_type = DP_REMOTE_I2C_READ;
>-	msg.u.i2c_read.num_transactions = num - 1;
>+	msg.u.i2c_read.num_transactions = count;
> 	msg.u.i2c_read.port_number = port->port_num;
>-	for (i = 0; i < num - 1; i++) {
>+	for (i = 0; i < count; i++) {
> 		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
> 		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
> 		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
> 	}
>-	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
>-	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
>+	msg.u.i2c_read.read_i2c_device_id = msgs[count].addr;
>+	msg.u.i2c_read.num_bytes_read = msgs[count].len;
> 
> 	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
>-	if (!txmsg) {
>+	if (unlikely(!txmsg)) {
> 		ret = -ENOMEM;
> 		goto out;
> 	}
>@@ -2838,11 +2845,11 @@ static int drm_dp_mst_i2c_xfer(struct i2
> 			ret = -EREMOTEIO;
> 			goto out;
> 		}
>-		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
>+		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[count].len) {
> 			ret = -EIO;
> 			goto out;
> 		}
>-		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
>+		memcpy(msgs[count].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[count].len);
> 		ret = num;
> 	}
> out:

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