Hi Marcel, Johan, On Mon, Sep 12, 2016 at 9:47 AM, Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote: > Hi Johan, > >>>> Right now in all of the le_scan functions filter_dup is set to >>>> LE_SCAN_FILTER_DUP_ENABLE. This is not always desired with beacons as >>>> the content may change. I can force this by sending the HCI commands >>>> to enable scanning without this filter, but then the mgmt api (and >>>> DBUS) cannot be used for scanning. >>>> >>>> I was wondering if people had thoughts on making this configurable? >>> >>> Check out the SetDiscoveryFilter: >>> >>> https://git.kernel.org/cgit/bluetooth/bluez.git/tree/doc/adapter-api.txt >>> >>> When that is used it will not enable duplicated filter and in fact is >>> the only way to discover beacons which don't have discoverable flags >>> sets e.g. broadcaster. >> >> Actually Brennan is right that none of these methods disable duplicate >> filtering. All of the places in the kernel that set the LE scan >> parameters explicitly enable duplicate filtering. I suppose we should >> seriously consider extending the mgmt API to allow performing LE scan >> without the duplicate filtering. Right now the only way to do that is >> through raw HCI access. > > however when a driver sets the strict duplicate filtering quirk, then scanning will be restarted and thus new advertising data can be found. Im not sure what the quirk actually means but it doesn't look like it will be able to attend the RSSI filtering since the controller may omit results thus why I though duplicate was not enabled when filtering is. From the code it looks like the quirk would force restarting the scanning: /* If duplicate filtering does not report RSSI changes, then restart * scanning to ensure updated result with updated RSSI values. */ if (test_bit(HCI_QUIRK_STRICT_DUPLICATE_FILTER, &hdev->quirks)) { restart_le_scan(hdev); Isn't that a causing a little too many restarts? I wonder if there is anyone using this quirk in practice? And is this really worth it instead of just disabling the duplicate filter? -- Luiz Augusto von Dentz -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
