linux-kernel - Re: [PATCH v2 1/3] Bluetooth: btintel: Add firmware lock function

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Message-Id: <B50A91CA-7379-42F9-8335-8FE4A51BE66F@canonical.com>
Date:   Wed, 17 Jul 2019 22:08:30 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Marcel Holtmann <marcel@...tmann.org>
Cc:     Johannes Berg <johannes.berg@...el.com>,
        "Grumbach, Emmanuel" <emmanuel.grumbach@...el.com>,
        Luciano Coelho <luciano.coelho@...el.com>,
        Johan Hedberg <johan.hedberg@...il.com>, linuxwifi@...el.com,
        linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        linux-bluetooth@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/3] Bluetooth: btintel: Add firmware lock function

at 21:36, Marcel Holtmann <marcel@...tmann.org> wrote:

> Hi Kai-Heng,
>
>> When Intel 8260 starts to load Bluetooth firmware and WiFi firmware, by
>> calling btintel_download_firmware() and iwl_pcie_load_given_ucode_8000()
>> respectively, the Bluetooth btintel_download_firmware() aborts half way:
>> [   11.950216] Bluetooth: hci0: Failed to send firmware data (-38)
>>
>> Let btusb and iwlwifi load firmwares exclusively can avoid the issue, so
>> introduce a lock to use in btusb and iwlwifi.
>>
>> This issue still occurs with latest WiFi and Bluetooth firmwares.
>>
>> BugLink: https://bugs.launchpad.net/bugs/1832988
>>
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
>> ---
>> v2:
>> - Add bug report link.
>> - Rebase on latest wireless-next.
>>
>> drivers/bluetooth/btintel.c   | 14 ++++++++++++++
>> drivers/bluetooth/btintel.h   | 10 ++++++++++
>> include/linux/intel-wifi-bt.h |  8 ++++++++
>> 3 files changed, 32 insertions(+)
>> create mode 100644 include/linux/intel-wifi-bt.h
>>
>> diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
>> index bb99c8653aab..93ab18d6ddad 100644
>> --- a/drivers/bluetooth/btintel.c
>> +++ b/drivers/bluetooth/btintel.c
>> @@ -20,6 +20,8 @@
>>
>> #define BDADDR_INTEL (&(bdaddr_t) {{0x00, 0x8b, 0x9e, 0x19, 0x03, 0x00}})
>>
>> +static DEFINE_MUTEX(firmware_lock);
>> +
>> int btintel_check_bdaddr(struct hci_dev *hdev)
>> {
>> 	struct hci_rp_read_bd_addr *bda;
>> @@ -709,6 +711,18 @@ int btintel_download_firmware(struct hci_dev *hdev,  
>> const struct firmware *fw,
>> }
>> EXPORT_SYMBOL_GPL(btintel_download_firmware);
>>
>> +void btintel_firmware_lock(void)
>> +{
>> +	mutex_lock(&firmware_lock);
>> +}
>> +EXPORT_SYMBOL_GPL(btintel_firmware_lock);
>> +
>> +void btintel_firmware_unlock(void)
>> +{
>> +	mutex_unlock(&firmware_lock);
>> +}
>> +EXPORT_SYMBOL_GPL(btintel_firmware_unlock);
>> +
>
> so I am not in favor of this solution. The hardware guys should start  
> looking into fixing the firmware loading and provide proper firmware that  
> can be loaded at the same time.

Of course it’s much better to fix from hardware side.

>
> I am also not for sure penalizing all Intel Bluetooth/WiFi combos only  
> because one of them has a bug during simultaneous loading of WiFi and  
> Bluetooth firmware.

Yes, it’s not ideal.

>
> Frankly it would be better to detect a failed load and try a second time  
> instead of trying to lock each other out. The cross-contamination of WiFi  
> and Bluetooth drivers is just not clean.

Ok. Where do you think is better to handle it, Bluetooth core or USB core?

Kai-Heng

>
> Regards
>
> Marcel