[PATCH v2] gatt: Remove reading Service Changed characteristic after connected

[PATCH v2] gatt: Remove reading Service Changed characteristic after connected

[Andrzej Kaczmarek]

Service Changed characteristic is a control-point attribute thus it cannot be
read and attempting to do so will fail. Instead, server shall send indication
once enabled in CCC.

This change is due to "Erratum 3833 - Service Changed" (ESR05) which changed
characteristic value properties from 0x26 to 0x20.
---
 profiles/gatt/gas.c | 37 -------------------------------------
 1 file changed, 37 deletions(-)

diff --git a/profiles/gatt/gas.c b/profiles/gatt/gas.c
index 28d7fbf..d189221 100644
--- a/profiles/gatt/gas.c
+++ b/profiles/gatt/gas.c
@@ -161,37 +161,6 @@ static void indication_cb(const uint8_t *pdu, uint16_t len, gpointer user_data)
 	btd_device_gatt_set_service_changed(gas->device, start, end);
 }
 
-static void gatt_service_changed_cb(guint8 status, const guint8 *pdu,
-					guint16 plen, gpointer user_data)
-{
-	struct gas *gas = user_data;
-	uint16_t start, end;
-
-	if (status) {
-		error("Read GATT Service Changed failed: %s",
-						att_ecode2str(status));
-		return;
-	}
-
-	if (plen != 5) {
-		error("Service Changed: PDU length mismatch");
-		return;
-	}
-
-	start = att_get_u16(&pdu[1]);
-	end = att_get_u16(&pdu[3]);
-
-	if (gas->changed.start == start && gas->changed.end == end)
-		return;
-
-	gas->changed.start = start;
-	gas->changed.end = end;
-
-	DBG("GATT Service Changed start: 0x%04X end: 0x%04X", start, end);
-
-	btd_device_gatt_set_service_changed(gas->device, start, end);
-}
-
 static void gatt_descriptors_cb(guint8 status, const guint8 *pdu, guint16 len,
 							gpointer user_data)
 {
@@ -311,8 +280,6 @@ static void attio_connected_cb(GAttrib *attrib, gpointer user_data)
 	/* TODO: Read other GAP characteristics - See Core spec page 1739 */
 
 	/*
-	 * Always read the characteristic value in the first connection
-	 * since attribute handles caching is not supported at the moment.
 	 * When re-connecting <<Service Changed>> handle and characteristic
 	 * value doesn't need to read again: known information from the
 	 * previous interaction.
@@ -322,10 +289,6 @@ static void attio_connected_cb(GAttrib *attrib, gpointer user_data)
 
 		bt_uuid16_create(&uuid, GATT_CHARAC_SERVICE_CHANGED);
 
-		gatt_read_char_by_uuid(gas->attrib, gas->gatt.start,
-						gas->gatt.end, &uuid,
-						gatt_service_changed_cb, gas);
-
 		gatt_discover_char(gas->attrib, gas->gatt.start, gas->gatt.end,
 					&uuid, gatt_characteristic_cb, gas);
 	}
-- 
1.7.11.3

Re: [PATCH v2] gatt: Remove reading Service Changed characteristic after connected

[Johan Hedberg]

Hi Andrzej,

On Thu, Sep 06, 2012, Andrzej Kaczmarek wrote:
> Service Changed characteristic is a control-point attribute thus it
> cannot be read and attempting to do so will fail. Instead, server
> shall send indication once enabled in CCC.
> 
> This change is due to "Erratum 3833 - Service Changed" (ESR05) which
> changed characteristic value properties from 0x26 to 0x20.
> ---
>  profiles/gatt/gas.c | 37 -------------------------------------
>  1 file changed, 37 deletions(-)

Applied. Thanks.

Johan