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Subject: Re: [PATCH v2] Bluetooth: btusb: Add a new quirk to skip
 HCI_FLT_CLEAR_ALL on fake CSR controllers
From:   Marcel Holtmann <marcel@holtmann.org>
In-Reply-To: <4957ed07-36b8-58a0-2307-d2e6e2940527@gmail.com>
Date:   Mon, 7 Feb 2022 16:39:44 +0100
Cc:     Johan Hedberg <johan.hedberg@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        BlueZ <linux-bluetooth@vger.kernel.org>,
        linux-kernel@vger.kernel.org, Hans de Goede <hdegoede@redhat.com>
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Message-Id: <71CA3E33-9498-4970-BE1A-6308D4AEE054@holtmann.org>
References: <4957ed07-36b8-58a0-2307-d2e6e2940527@gmail.com>
To:     Ismael Ferreras Morezuelas <swyterzone@gmail.com>
Precedence: bulk

Hi Ismael,

> Another subset of the more recent batch of Chinese clones aren't
> specs-compliant and seem to lock up whenever they receive a
> HCI_OP_SET_EVENT_FLT with flt_type set to zero/HCI_FLT_CLEAR_ALL,
> which on Linux happens right at BR/EDR setup.
> 
> So, while all the previous efforts to wrangle the herd of fake CSRs
> seem to be paying off (and these also get detected as such) we
> still need to take care of this quirk; testers seem to agree
> that these dongles tend to work well enough afterwards.
> 
> From some cursory USB packet capture on Windows it seems like
> that driver doesn't appear to use this clear-all functionality at all.
> 
> This patch was tested on some really popular AliExpress-style
> dongles, in my case marked as "V5.0". Chip markings: UG8413,
> the backside of the PCB says "USB Dangel" (sic).
> 
> Here is the `hciconfig -a` output; for completeness:
> 
> hci0:	Type: Primary  Bus: USB
> 	BD Address: 00:1A:7D:DA:7X:XX  ACL MTU: 679:8  SCO MTU: 48:16
> 	UP RUNNING PSCAN ISCAN
> 	Features: 0xbf 0x3e 0x4d 0xfa 0xdb 0x3d 0x7b 0xc7
> 	Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
> 	Link policy: RSWITCH SNIFF
> 	Link mode: PERIPHERAL ACCEPT
> 	Name: 'CSR8510 A10.'
> 	Class: 0x7c0104
> 	Service Classes: Rendering, Capturing, Object Transfer, Audio, Telephony
> 	Device Class: Computer, Desktop workstation
> 	HCI Version: 4.0 (0x6)  Revision: 0x3120
> 	LMP Version: 4.0 (0x6)  Subversion: 0x22bb
> 	Manufacturer: Cambridge Silicon Radio (10)
> 
> As well as the `lsusb -vv -d 0a12:0001`:
> 
> ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
> Device Descriptor:
>  bLength                18
>  bDescriptorType         1
>  bcdUSB               2.00
>  bDeviceClass          224 Wireless
>  bDeviceSubClass         1 Radio Frequency
>  bDeviceProtocol         1 Bluetooth
>  bMaxPacketSize0        64
>  idVendor           0x0a12 Cambridge Silicon Radio, Ltd
>  idProduct          0x0001 Bluetooth Dongle (HCI mode)
>  bcdDevice           88.91
>  iManufacturer           0
>  iProduct                2 BT DONGLE10
>  iSerial                 0
>  bNumConfigurations      1
> 
> Also, changed the benign dmesg print that shows up whenever the
> generic force-suspend fails from bt_dev_err to bt_dev_warn;
> it's okay and done on a best-effort basis, not a problem
> if that does not work.
> 
> Also, swapped the HCI subver and LMP subver numbers for the Barrot
> in the comment, which I copied wrong the last time around.
> 
> Fixes: 81cac64ba258a ("Bluetooth: Deal with USB devices that are faking CSR vendor")
> Fixes: cde1a8a992875 ("Bluetooth: btusb: Fix and detect most of the Chinese Bluetooth controllers")
> Fixes: d74e0ae7e0303 ("Bluetooth: btusb: Fix detection of some fake CSR controllers with a bcdDevice val of 0x0134")
> Fixes: 0671c0662383e ("Bluetooth: btusb: Add workaround for remote-wakeup issues with Barrot 8041a02 fake CSR controllers")
> Fixes: f4292e2faf522 ("Bluetooth: btusb: Make the CSR clone chip force-suspend workaround more generic")
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=60824
> https://gist.github.com/nevack/6b36b82d715dc025163d9e9124840a07
> 
> Cc: stable@vger.kernel.org
> Cc: Hans de Goede <hdegoede@redhat.com>
> Tested-by: Gonzalo Tornaría <tornaria@cmat.edu.uy>
> Tested-by: Mateus Lemos <lemonsmateus@gmail.com>
> Tested-by: Ismael Ferreras Morezuelas <swyterzone@gmail.com>
> Signed-off-by: Ismael Ferreras Morezuelas <swyterzone@gmail.com>
> ---
> 
> Changes for v2:
>  * Added HCI_QUIRK_NO_SUSPEND_NOTIFIER to btusb_setup_csr().
>    In theory we already disable runtime suspend in btusb, button
>    better safe than sorry. Doesn't hurt to explicitly avoid the
>    hci_suspend_dev() codepath, it also works as example.
>  * Improved the quirk description in hci.h, as suggested by Hans
>    de Goede. Explain the need to disable runtime suspend.
>  * Also check for the quirk in hci_req_set_event_filter();
>    mirror its hci_req_clear_event_filter() counterpart.
>  * The struct hci_dev *hdev variables always go first.
>  * Removed some misc formatting changes.
> 
> The dongles still seem all peachy after the v2 changes. :)
> 
> drivers/bluetooth/btusb.c   |  6 ++++--
> include/net/bluetooth/hci.h | 10 ++++++++++
> net/bluetooth/hci_core.c    | 11 ++++++++---
> net/bluetooth/hci_request.c | 13 ++++++++++---
> 4 files changed, 32 insertions(+), 8 deletions(-)

the patch no longer applies cleanly against bluetooth-next tree. Please send an updated version.

Regards

Marcel