Public bug reported:

The Broadcom Bluetooth kernel module supports loading patches for
specific hardware devices. Which devices require patchram support is
defined in an array of structs in the kernel module `btusb`, which allow
matching by Vendor ID and, optionally, Product ID.

The Dell-branded device `413c:8197` requires the patch
`BCM20702A1-413c-8197.hcd`[1] to be loaded in order for HSP/HFP
functionality to work (A2DP and AVRCP work without the patch). However,
the patch is not sought for this device by `btusb`.

In 2011, `413c:8197` was included in the module[2], but not marked as
requiring patchram. Later, in 2017, a blanket entry was added for all
Dell-branded (`413c`) devices[3], marking them as requiring patchram.
However, the previous entry for `413c:8197` was not removed and appears
to block the patchram requirement from being added for this device
(presumably the algorithm stops searching after the first match). The
code stands like so:

```
static const struct usb_device_id btusb_table[] = {
...
        /* Broadcom BCM20702A0 */
        { USB_DEVICE(0x413c, 0x8197) },
...
        /* Dell Computer - Broadcom based  */
        { USB_VENDOR_AND_INTERFACE_INFO(0x413c, 0xff, 0x01, 0x01),
          .driver_info = BTUSB_BCM_PATCHRAM },
```

I would like to request removal of the earlier entry to facilitate
patchram support for device `413c:8197`.

I have tested this as working on my Dell Precision M6700 running Ubuntu
20.04 with kernel `5.4.0-71-generic`.

[1]: 
https://github.com/winterheart/broadcom-bt-firmware/blob/master/brcm/BCM20702A1-413c-8197.hcd
[2]: 
https://github.com/torvalds/linux/commit/d13431ca3eb2a2c14314f04813cdc11cd869f150
[3]: 
https://github.com/torvalds/linux/commit/fdfddc601713d4ed564b0bd25b29415bd622020a

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1924741

Title:
  Load Broadcom firmware for Dell Bluetooth device [413c:8197]

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1924741/+subscriptions

-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to