Re: [4.15 stable regression] "Bluetooth: btusb: Fix quirk for Atheros 1525/QCA6174" breaks bluetooth on some devices

[Takashi Iwai <tiwai@suse.de>]

On Wed, 25 Apr 2018 14:49:59 +0200,
Hans de Goede wrote:
> 
> Hi,
> 
> On 25-04-18 14:47, Greg Kroah-Hartman wrote:
> > On Wed, Apr 25, 2018 at 02:40:37PM +0200, Hans de Goede wrote:
> >> Hi,
> >>
> >> On 18-04-18 15:18, Hans de Goede wrote:
> >>> Hi Takashi, Marcel,
> >>>
> >>> It seems that this commit:
> >>> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/commit/?h=linux-4.15.y&id=7ec32f585fefd7c154453aa29ccf8fa2a11cc865
> >>>
> >>> Is breaking bluetooth on some devices, see:
> >>>
> >>> https://bugzilla.redhat.com/show_bug.cgi?id=1568911
> >>>
> >>> The problem is the following error now being thrown:
> >>>
> >>> [   28.466248] Bluetooth: hci0: don't support firmware rome 0x1020200
> >>>
> >>> Looking at the code I wonder if maybe we need to mask the ver_rom
> >>> with & 0xfff when comparing it to the qca_devices_table[i].rom_version
> >>> filed ?
> >>>
> >>> Or maybe the commit is actually wrong, or maybe devices with the
> >>> 0cf3:3004 USB id need either the BTUSB_QCA_ROM or BTUSB_ATH3012
> >>> quirk depending on the device and we need to probe this somehow?
> >>
> >> I've been receiving more complaints from users about this on
> >> various devices, so I think that the 7ec32f585fefd7c154453aa29ccf8fa2a11cc865
> >> commit should be reverted from 4.15.x while we figure this out.
> >>
> >> Does anyone have any idea how we cam distinguish between the 2
> >> different versions which seem to be hiding between the same USB-id ?
> >
> > 4.15.y is end-of-life, so there is no more releases being made for it,
> > sorry.
> 
> Ah, right, no problem, Fedora should be moving to 4.16.x soon then
> anyways.
> 
> > But, this commit is in 4.4.y, 4.9.y, 4.14.y, and 4.16.  Can you revert
> > it in Linus's tree and I can revert it everywhere else as well?
> 
> Takashi, do you agree that reverting this for now is best? And if so
> can you please send a revert?

The best would be to fix it properly :)

But I agree that it needs a quick resolution, and the revert is
appropriate in this case.  Since you've confirmed that the revert
worked, feel free to submit the revert patch from your side.

Back to the original issue: now I'm wondering what made such
inconsistent behavior.  My current suspect is the racy driver loading
between btusb and ath3k.  Both have the same USB ID, and the driver
loading order may interfere the behavior with each other?

Or might it be a WiFi/BT combo chip that may have a racy firmware
initialization?


thanks,

Takashi