Message-ID: <643d8055-5a9f-4f5b-865b-830d33651dfe@leemhuis.info>
Date: Fri, 1 Nov 2024 15:22:13 +0100
From: Thorsten Leemhuis <regressions@...mhuis.info>
To: "luiz.dentz@...il.com" <luiz.dentz@...il.com>,
 "tiwai@...e.de" <tiwai@...e.de>
Cc: "marcel@...tmann.org" <marcel@...tmann.org>,
 "linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "linux-bluetooth@...r.kernel.org" <linux-bluetooth@...r.kernel.org>,
 Deren Wu (武德仁) <Deren.Wu@...iatek.com>,
 "regressions@...ts.linux.dev" <regressions@...ts.linux.dev>,
 "johan.hedberg@...il.com" <johan.hedberg@...il.com>,
 Steve Lee (李視誠) <steve.lee@...iatek.com>,
 "marc.payne@...sys.co.uk" <marc.payne@...sys.co.uk>,
 Sean Wang <Sean.Wang@...iatek.com>, Aaron Hou (侯俊仰)
 <Aaron.Hou@...iatek.com>, Chris Lu (陸稚泓)
 <Chris.Lu@...iatek.com>, Hao Qin (秦浩)
 <Hao.Qin@...iatek.com>
Subject: Re: [PATCH] Bluetooth: btmtk: Remove resetting mt7921 before
 downloading the fw

Hi. Top-posting for once, to make this easily accessible to everyone.

Thx for the insights, but it feels like this is not the complete story.
>From Takashi's mail earlier in the thread it appears to me that there is
a regression that the patch at the start of the thread fixes:
https://lore.kernel.org/all/87iktk4d9l.wl-tiwai@suse.de/

So it appears to me (please correct me if I'm wrong, which I might be)
there is some regression that must be fixed independently of any
firmware changes; not sure, maybe it's a different regression that the
one Marc saw.

I just don't know what's the best way forward to resolve the regresson.
A revert of the culprit? The patch at the start of this thread?
Something else?

Takashi, Luiz, can you help me out here? I guess I otherwise soon will
have to involve higher level maintainers to sort this out (e.g. the -net
maintainers and/or Linus).

Ciao, Thorsten

On 01.11.24 08:11, Chris Lu (陸稚泓) wrote:
> Hi Thorsten,
> 
> On Wed, 2024-10-30 at 12:29 +0100, Thorsten Leemhuis wrote:
>> External email : Please do not click links or open attachments until
>> you have verified the sender or the content.
>> 
>> 
>> On 30.10.24 12:03, Chris Lu (陸稚泓) wrote:
>> > 
>> > Let me recap and update the status of this problem.
>> 
>> Many thx!
>> 
>> > Marc feedback that he has some problem with MT7921AUN usb module.
>> > Originally, we thought it was caused by the change "Fixes:
>> > ccfc8948d7e4d9 ("Bluetooth: btusb: mediatek: reset the controller
>> > before downloading the fw")". The change is mainly for MT7922, we
>> > found some problem with MT7921 on specific platform internally. As
>> > a result, Hao sent another patch to remove MT7921 from that
>> > rule(Bluetooth: btmtk: Remove resetting mt7921 before downloading
>> > the fw).
>> > 
>> > However, Marc also mentioned that BT is able to work if changing
>> > back
>> > to an old firmware bin. Based on the clue, we found it was caused
>> > by a
>> > firmware change that specific MT7921 model will not able to setup
>> > successfully. (In fact, we didn't expect that MT7921AUN can be get
>> > by
>> > normal user.)
>> > 
>> > Since we can't predict which model user use and Luiz also suggests
>> > MediaTek to fix it if that model can work before, we have prepared
>> > a
>> > solution. I've verified the solution locally that MT7921AUN model
>> > can
>> > work normally on Ubuntu PC. It will be a firmware modification. We
>> > plan
>> > to submit new firmware with this modification in 2024 Nov.
>> 
>> Great, but due to the kernel's "no regressions" rule this is mostly
>> irrelevant, as the regression must be fixed in a way that does not
>> require users to change their firmware.
>> 
> 
> Marc's module(MT7921AUN) is not working is due to a change in specific
> firmware uploaded last year and we plan to revert that in the next
> firmware release. Since it's related to controller's behavior, it's
> quite hard to cover in software side.
> Additionally, MT7921AUN is an external usb dongle. MediaTek official PC
> project doesn't use this type of MT7921 model. We uses another type for
> PC projects that it can be guaranteed bluetooth works normally with any
> firmware we upload to Kernel. As a result, we believe the impact is
> minimal to general user.
> 
>> So is any such solution in sight? Or should we just revert
>> ccfc8948d7e4d9 and any related follow up patches for now? Or would
>> that
>> just cause regressions for other users?
>> 
> 
> Actually, it's not related to ccfc8948d7e4d9 which make bluetooth can't
> setup normally if using MT7921AUN model + mismatched firmware. We
> thought it was the same issue in the beginning, but it's not eventually
> after getting more and more clue/logs.
> I think we can keep the change because it's necessary to the change
> submitter-Hao's project.
> 
> Chris Lu
> 
>> Ciao, Thorsten
>> 
>> > On Wed, 2024-10-30 at 10:21 +0100, Thorsten Leemhuis wrote:
>> > > External email : Please do not click links or open attachments
>> > > until
>> > > you have verified the sender or the content.
>> > > 
>> > > 
>> > > Hi, Thorsten here, the Linux kernel's regression tracker. Top-
>> > > posting
>> > > for once, to make this easily accessible to everyone.
>> > > 
>> > > I'm a bit lost here, but maybe I'm missing something.
>> > > 
>> > > Luiz, can you help out here? Is there a reason why this patch is
>> > > not
>> > > making any process?
>> > > 
>> > > Chris Lu and/or Hao Qin: Can you maybe help out as well as well
>> > > and
>> > > help
>> > > with resolving some open questions that might or might not be
>> > > relevant
>> > > (see below).
>> > > 
>> > > From Takashi reply, the bugzilla ticket he linked to, and the
>> > > mail
>> > > from
>> > > the MediaTek folks
>> > > (
>> > > 
> https://lore.kernel.org/lkml/12a344e25b31ec00fe8b57814d43fcb166e71be5.camel@mediatek.com/
>> > > ) it from the outside looks like this patch should really be
>> > > merged
>> > > rather sooner that later as it fixes regressions for some people.
>> > > Afaics it should get a "Fixes: ccfc8948d7e4d9 ("Bluetooth: btusb:
>> > > mediatek: reset the controller before downloading the fw")" tag,
>> > > as
>> > > it's
>> > > afaics that commit that causes the regression that is known since
>> > > more
>> > > than three months now
>> > > (https://lore.kernel.org/all/ZsTh7Jyug7MbZsLE@mdpsys.co.uk/ ).
>> > > 
>> > > But note, it seems it does not fix the regression completely
>> > > according
>> > > to Marc's testing.
>> > > https://lore.kernel.org/all/ZuCB98DSdtKCgxaL@mdpsys.co.uk/
>> > > 
>> > > Marc: Is that still how things are with current mainline?
>> > > 
>> > > Ciao, Thorsten
>> > > 
>> > > 
>> > > On 22.10.24 12:56, Takashi Iwai wrote:
>> > > > On Mon, 14 Oct 2024 11:29:40 +0200,
>> > > > Linux regression tracking (Thorsten Leemhuis) wrote:
>> > > > > 
>> > > > > On 20.09.24 08:27, Chris Lu (陸稚泓) wrote:
>> > > > > > On Thu, 2024-09-19 at 23:25 +0100, marc.payne@...sys.co.uk
>> > > > > > wrote:
>> > > > > > > 
>> > > > > > > External email : Please do not click links or open
>> > > > > > > attachments until
>> > > > > > > you have verified the sender or the content.
>> > > > > > >  Hi Chris and Luiz,
>> > > > > > > 
>> > > > > > > What were your thoughts on the findings in my email dated
>> > > > > > > 18th
>> > > > > > > September?
>> > > > > > 
>> > > > > > Thanks for your suggestion.
>> > > > > > 
>> > > > > > I've prepared the same environment (Kernel v6.11 +
>> > > > > > MT7921AUN
>> > > > > > dongle) to
>> > > > > > reproduce the issue, collected necessary logs locally and
>> > > > > > also
>> > > > > > initiated an internal discussion to clarify the root cause
>> > > > > > of
>> > > > > > this
>> > > > > > symptom. We'll review the changes between two firmware
>> > > > > > (20230526/20231109) if it's a bug or not.
>> > > > > > 
>> > > > > > It may take some time to investigate. I'll let you know if
>> > > > > > there is any
>> > > > > > progress.
>> > > > > 
>> > > > > Just wondering: Chris Lu, and Marc, what's the status here?
>> > > > > From
>> > > > > here it
>> > > > > looks like there was no progress to fix this regression for a
>> > > > > while, but
>> > > > > it's easy to miss something, that's why I ask.
>> > > > > 
>> > > > > Ciao, Thorsten
>> > > > 
>> > > > FWIW, the similar bug was reported for the recent 6.11.x kernel
>> > > > on
>> > > > openSUSE Tumbleweed, and this patch was confirmed to work
>> > > > around
>> > > > the
>> > > > crash at boot:
>> > > > 
>> > > > 
> https://urldefense.com/v3/__https://bugzilla.suse.com/show_bug.cgi?id=1231599__;!!CTRNKA9wMg0ARbw!jYyH2oubBEtIKXmKl9cI2rrmK-7kSdaiIJQ8xH4NZa5i5YCTQDHaoOxCBhMgdAAY6ROIPAoPwbOV-LNeMRJBlR6u-As$
>> > > > 
>> > > > It'd be great if you can go ahead and merge the proper fix to
>> > > > the
>> > > > upstream.
>> > > > 
>> > > > Let me know if you have another patch to test.  Then I can
>> > > > create a
>> > > > test kernel package and ask the bug reporter for testing.
>> > > > 
>> > > > 
>> > > > thanks,
>> > > > 
>> > > > Takashi
>> > > > 
>> > > 
>> > > 
>> > 
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>> 
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