* [PATCH] gatt: Remove reading Service Changed characteristic after connected
@ 2012-09-06 10:53 Andrzej Kaczmarek
2012-09-06 13:56 ` Claudio Takahasi
0 siblings, 1 reply; 3+ messages in thread
From: Andrzej Kaczmarek @ 2012-09-06 10:53 UTC (permalink / raw)
To: linux-bluetooth; +Cc: 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.
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] gatt: Remove reading Service Changed characteristic after connected
2012-09-06 10:53 [PATCH] gatt: Remove reading Service Changed characteristic after connected Andrzej Kaczmarek
@ 2012-09-06 13:56 ` Claudio Takahasi
2012-09-07 7:49 ` Andrzej Kaczmarek
0 siblings, 1 reply; 3+ messages in thread
From: Claudio Takahasi @ 2012-09-06 13:56 UTC (permalink / raw)
To: Andrzej Kaczmarek; +Cc: linux-bluetooth
Hi Andrzej:
On Thu, Sep 6, 2012 at 7:53 AM, Andrzej Kaczmarek
<andrzej.kaczmarek@tieto.com> 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.
> ---
> 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
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
As discussed in the IRC, please add in the commit message the BT SPEC
errata information/section.
Since we can't read the characteristic value, it will be necessary to
store the handle, otherwise BlueZ will loose the Service Changed
Indication when re-connecting.
Regards,
Claudio
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] gatt: Remove reading Service Changed characteristic after connected
2012-09-06 13:56 ` Claudio Takahasi
@ 2012-09-07 7:49 ` Andrzej Kaczmarek
0 siblings, 0 replies; 3+ messages in thread
From: Andrzej Kaczmarek @ 2012-09-07 7:49 UTC (permalink / raw)
To: Claudio Takahasi; +Cc: linux-bluetooth@vger.kernel.org
Hi Claudio,
On 09/06/2012 03:56 PM, Claudio Takahasi wrote:
> Hi Andrzej:
>
> On Thu, Sep 6, 2012 at 7:53 AM, Andrzej Kaczmarek
> <andrzej.kaczmarek@tieto.com> wrote:
<snip>
>> 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
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> As discussed in the IRC, please add in the commit message the BT SPEC
> errata information/section.
>
> Since we can't read the characteristic value, it will be necessary to
> store the handle, otherwise BlueZ will loose the Service Changed
> Indication when re-connecting.
Handle is already stored during characteristics discovery
(gatt_characteristic_cb) so this should not be a problem.
BR,
Andrzej
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-09-06 10:53 [PATCH] gatt: Remove reading Service Changed characteristic after connected Andrzej Kaczmarek
2012-09-06 13:56 ` Claudio Takahasi
2012-09-07 7:49 ` Andrzej Kaczmarek
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