Merge branch 'drm-fixes-mst' of git://people.freedesktop.org/~airlied/linux into drm-fixes

displayport multistream fixes from AMD.

* 'drm-fixes-mst' of git://people.freedesktop.org/~airlied/linux:
  drm/dp/mst: deallocate payload on port destruction
  drm/dp/mst: Reverse order of MST enable and clearing VC payload table.
  drm/dp/mst: move GUID storage from mgr, port to only mst branch
  drm/dp/mst: change MST detection scheme
  drm/dp/mst: Calculate MST PBN with 31.32 fixed point
  drm: Add drm_fixp_from_fraction and drm_fixp2int_ceil
  drm/mst: Add range check for max_payloads during init
  drm/mst: Don't ignore the MST PBN self-test result
  drm: fix missing reference counting decrease

include/drm/drm_dp_mst_helper.h

@@ -44,8 +44,6 @@ struct drm_dp_vcpi {
 /**
  * struct drm_dp_mst_port - MST port
  * @kref: reference count for this port.
- * @guid_valid: for DP 1.2 devices if we have validated the GUID.
- * @guid: guid for DP 1.2 device on this port.
  * @port_num: port number
  * @input: if this port is an input port.
  * @mcs: message capability status - DP 1.2 spec.
@@ -70,10 +68,6 @@ struct drm_dp_vcpi {
 struct drm_dp_mst_port {
 	struct kref kref;
 
-	/* if dpcd 1.2 device is on this port - its GUID info */
-	bool guid_valid;
-	u8 guid[16];
-
 	u8 port_num;
 	bool input;
 	bool mcs;
@@ -110,10 +104,12 @@ struct drm_dp_mst_port {
  * @tx_slots: transmission slots for this device.
  * @last_seqno: last sequence number used to talk to this.
  * @link_address_sent: if a link address message has been sent to this device yet.
+ * @guid: guid for DP 1.2 branch device. port under this branch can be
+ * identified by port #.
  *
  * This structure represents an MST branch device, there is one
- * primary branch device at the root, along with any others connected
- * to downstream ports
+ * primary branch device at the root, along with any other branches connected
+ * to downstream port of parent branches.
  */
 struct drm_dp_mst_branch {
 	struct kref kref;
@@ -132,6 +128,9 @@ struct drm_dp_mst_branch {
 	struct drm_dp_sideband_msg_tx *tx_slots[2];
 	int last_seqno;
 	bool link_address_sent;
+
+	/* global unique identifier to identify branch devices */
+	u8 guid[16];
 };
 
 
@@ -406,11 +405,9 @@ struct drm_dp_payload {
  * @conn_base_id: DRM connector ID this mgr is connected to.
  * @down_rep_recv: msg receiver state for down replies.
  * @up_req_recv: msg receiver state for up requests.
- * @lock: protects mst state, primary, guid, dpcd.
+ * @lock: protects mst state, primary, dpcd.
  * @mst_state: if this manager is enabled for an MST capable port.
  * @mst_primary: pointer to the primary branch device.
- * @guid_valid: GUID valid for the primary branch device.
- * @guid: GUID for primary port.
  * @dpcd: cache of DPCD for primary port.
  * @pbn_div: PBN to slots divisor.
  *
@@ -432,13 +429,11 @@ struct drm_dp_mst_topology_mgr {
 	struct drm_dp_sideband_msg_rx up_req_recv;
 
 	/* pointer to info about the initial MST device */
-	struct mutex lock; /* protects mst_state + primary + guid + dpcd */
+	struct mutex lock; /* protects mst_state + primary + dpcd */
 
 	bool mst_state;
 	struct drm_dp_mst_branch *mst_primary;
-	/* primary MST device GUID */
-	bool guid_valid;
-	u8 guid[16];
+
 	u8 dpcd[DP_RECEIVER_CAP_SIZE];
 	u8 sink_count;
 	int pbn_div;

include/drm/drm_fixed.h

@@ -73,18 +73,28 @@ static inline u32 dfixed_div(fixed20_12 A, fixed20_12 B)
 #define DRM_FIXED_ONE		(1ULL << DRM_FIXED_POINT)
 #define DRM_FIXED_DECIMAL_MASK	(DRM_FIXED_ONE - 1)
 #define DRM_FIXED_DIGITS_MASK	(~DRM_FIXED_DECIMAL_MASK)
+#define DRM_FIXED_EPSILON	1LL
+#define DRM_FIXED_ALMOST_ONE	(DRM_FIXED_ONE - DRM_FIXED_EPSILON)
 
 static inline s64 drm_int2fixp(int a)
 {
 	return ((s64)a) << DRM_FIXED_POINT;
 }
 
-static inline int drm_fixp2int(int64_t a)
+static inline int drm_fixp2int(s64 a)
 {
 	return ((s64)a) >> DRM_FIXED_POINT;
 }
 
-static inline unsigned drm_fixp_msbset(int64_t a)
+static inline int drm_fixp2int_ceil(s64 a)
+{
+	if (a > 0)
+		return drm_fixp2int(a + DRM_FIXED_ALMOST_ONE);
+	else
+		return drm_fixp2int(a - DRM_FIXED_ALMOST_ONE);
+}
+
+static inline unsigned drm_fixp_msbset(s64 a)
 {
 	unsigned shift, sign = (a >> 63) & 1;
 
@@ -136,6 +146,45 @@ static inline s64 drm_fixp_div(s64 a, s64 b)
 	return result;
 }
 
+static inline s64 drm_fixp_from_fraction(s64 a, s64 b)
+{
+	s64 res;
+	bool a_neg = a < 0;
+	bool b_neg = b < 0;
+	u64 a_abs = a_neg ? -a : a;
+	u64 b_abs = b_neg ? -b : b;
+	u64 rem;
+
+	/* determine integer part */
+	u64 res_abs  = div64_u64_rem(a_abs, b_abs, &rem);
+
+	/* determine fractional part */
+	{
+		u32 i = DRM_FIXED_POINT;
+
+		do {
+			rem <<= 1;
+			res_abs <<= 1;
+			if (rem >= b_abs) {
+				res_abs |= 1;
+				rem -= b_abs;
+			}
+		} while (--i != 0);
+	}
+
+	/* round up LSB */
+	{
+		u64 summand = (rem << 1) >= b_abs;
+
+		res_abs += summand;
+	}
+
+	res = (s64) res_abs;
+	if (a_neg ^ b_neg)
+		res = -res;
+	return res;
+}
+
 static inline s64 drm_fixp_exp(s64 x)
 {
 	s64 tolerance = div64_s64(DRM_FIXED_ONE, 1000000);