Re: [RFC PATCH v2] Bluetooth: btintel: Fix broken LED quirk for legacy ROM devices

Hi Marcel,

On Thu, 2021-12-23 at 00:08 +0100, Marcel Holtmann wrote:

Hi Tedd,

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This patch fixes the broken LED quirk for Intel legacy ROM devices.
To fix the LED issue that doesn't turn off immediately, the host sends
the SW RFKILL command while shutting down the interface and it puts the
devices in an asserted state.

Once the device is in SW RFKILL state, it can only accept HCI_Reset to
exit from the SW RFKILL state. This patch checks the quirk and sends the
HCI_Reset before sending the HCI_Intel_Read_Version command.

The affected legacy ROM devices are
- 8087:0a2a
- 8087:0aa7

fixes: ffcba827c0a1d ("Bluetooth: btintel: Fix the LED is not turning
off
immediately")

Signed-off-by: Tedd Ho-Jeong An <redacted>
---
drivers/bluetooth/btintel.c | 13 ++++++-------
drivers/bluetooth/btusb.c   | 10 ++++++++--
2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/bluetooth/btintel.c b/drivers/bluetooth/btintel.c
index e1f96df847b8..75f8d7aceb35 100644
--- a/drivers/bluetooth/btintel.c
+++ b/drivers/bluetooth/btintel.c

@@ -2355,8 +2355,13 @@ static int btintel_setup_combined(struct hci_dev

*hdev)
         * As a workaround, send HCI Reset command first which will
reset the
         * number of completed commands and allow normal command
processing
         * from now on.
+        *
+        * For INTEL_BROKEN_LED, these devices have an issue with LED
which
+        * doesn't go off immediately during shutdown. Set the flag here
to
send
+        * the LED OFF command during shutdown.
         */
-       if (btintel_test_flag(hdev, INTEL_BROKEN_INITIAL_NCMD)) {
+       if (btintel_test_flag(hdev, INTEL_BROKEN_INITIAL_NCMD) ||
+                               btintel_test_flag(hdev,
INTEL_BROKEN_LED)) {
                skb = __hci_cmd_sync(hdev, HCI_OP_RESET, 0, NULL,
                                     HCI_INIT_TIMEOUT);
                if (IS_ERR(skb)) {

@@ -2428,12 +2433,6 @@ static int btintel_setup_combined(struct hci_dev

*hdev)
                               
set_bit(HCI_QUIRK_WIDEBAND_SPEECH_SUPPORTED,
                                        &hdev->quirks);

-                       /* These devices have an issue with LED which
doesn't
-                        * go off immediately during shutdown. Set the
flag
-                        * here to send the LED OFF command during
shutdown.
-                        */
-                       btintel_set_flag(hdev, INTEL_BROKEN_LED);
-
                        err = btintel_legacy_rom_setup(hdev, &ver);
                        break;
                case 0x0b:      /* SfP */

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index d1bd9ee0a6ab..c6a070d5284f 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c

@@ -60,6 +60,7 @@ static struct usb_driver btusb_driver;

#define BTUSB_WIDEBAND_SPEECH   0x400000
#define BTUSB_VALID_LE_STATES   0x800000
#define BTUSB_QCA_WCN6855       0x1000000
+#define BTUSB_INTEL_BROKEN_LED 0x2000000
#define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000

static const struct usb_device_id btusb_table[] = {

@@ -382,9 +383,11 @@ static const struct usb_device_id blacklist_table[]

= {
        { USB_DEVICE(0x8087, 0x07da), .driver_info = BTUSB_CSR },
        { USB_DEVICE(0x8087, 0x07dc), .driver_info =
BTUSB_INTEL_COMBINED |
                                                    
BTUSB_INTEL_BROKEN_INITIAL_NCMD },
-       { USB_DEVICE(0x8087, 0x0a2a), .driver_info =
BTUSB_INTEL_COMBINED },
+       { USB_DEVICE(0x8087, 0x0a2a), .driver_info =
BTUSB_INTEL_COMBINED |
+                                                   
BTUSB_INTEL_BROKEN_LED },
        { USB_DEVICE(0x8087, 0x0a2b), .driver_info =
BTUSB_INTEL_COMBINED },
-       { USB_DEVICE(0x8087, 0x0aa7), .driver_info =
BTUSB_INTEL_COMBINED },
+       { USB_DEVICE(0x8087, 0x0aa7), .driver_info =
BTUSB_INTEL_COMBINED |
+                                                   
BTUSB_INTEL_BROKEN_LED },
        { USB_DEVICE(0x8087, 0x0aaa), .driver_info =
BTUSB_INTEL_COMBINED },

this is the part that I tried to avoid.

I remembered it but I couldn't find any other way. 

I already tried the method below but it didn't work especially for the
reboot
(warm boot) case becase the platform keeps the USB power while rebooting the
system and BT device is still in the SW RFKILL state. 
The flag sets in the btintel_shutdown_combined() doesn't stay because the
HDEV
and the driver data are freed and allocated again while rebooting. So the
intel_flag_test_and_clear(INTEL_SHUTDOWN_EXECUTED) is never TRUE.

this is the part that I don’t grok. So how do we reset the USB power while
still keeping it. Does this mean we see a USB Disconnect and USB Reconnect
happening, but the second time around we enter btusb_probe() we come from a
total different state?

And how does it make sense that calling hdev->shutdown() ends up in
btusb_remove() + btusb_probe(). I am confused.

I think I didn't explan the test case enough. There is no issue if the HCI is up
before rebooting the system. The issue is reproducible only when the HCI
interface is down and reboot.

For example, the steps are:
1. Bluetooth daemon is not running (actually it doesn't matter)
2. Put HCI Down and it causes hdev->shutdown()->btintel_shutdown_combined()
3. Now StP is in SW RFKILL state
4. Reboot
5. btintel_setup_combined() is called
6. HCI_Intel_Read_Version command failed.

So, the flag value set before the reboot is no longer available/valid after
reboot. Also, while rebooting, I don't see USB disconnect and the device state
is same as before the reboot.

Regards

Marcel