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Date: Mon, 04 Mar 2024 13:45:30 +0100
Message-ID: <874jdm17yt.wl-tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Javier Carrasco <javier.carrasco@wolfvision.net>
Cc: Takashi Iwai <tiwai@suse.de>,
	Javier Carrasco <javier.carrasco.cruz@gmail.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	linux-input@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	regressions@lists.linux.dev
Subject: Re: [REGRESSION] Missing bcm5974 touchpad on Macbooks
In-Reply-To: <6ef6c5bf-e6e5-4711-81c6-6ae41de2e61e@wolfvision.net>
References: <87sf161jjc.wl-tiwai@suse.de>
	<6ef6c5bf-e6e5-4711-81c6-6ae41de2e61e@wolfvision.net>
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On Mon, 04 Mar 2024 12:26:48 +0100,
Javier Carrasco wrote:
> 
> On 04.03.24 09:35, Takashi Iwai wrote:
> > Hi,
> > 
> > we've received a few regression reports for openSUSE Leap about the
> > missing touchpad on Macbooks.  After debugging, this turned out to be
> > the backport of the commit 2b9c3eb32a699acdd4784d6b93743271b4970899
> >     Input: bcm5974 - check endpoint type before starting traffic
> > 
> > And, the same regression was confirmed on the upstream 6.8-rc6
> > kernel.
> > 
> > Reverting the commit above fixes the problem, the touchpad reappears.
> > 
> > The detailed hardware info is found at:
> >   https://bugzilla.suse.com/show_bug.cgi?id=1220030
> > 
> > Feel free to join the bugzilla above, or let me know if you need
> > something for debugging, then I'll delegate on the bugzilla.
> > 
> > 
> > thanks,
> > 
> > Takashi
> > 
> 
> Hi Takashi,
> 
> The commit adds a check to ensure that the endpoint type is interrupt.
> 
> According to that report, the issue arose with a MacBook Pro 5.1 (no
> button, only trackpad endpoint), so the check on the tp_ep address
> (0x81) returns false. I assume that you see an error message
> ("Unexpected non-int endpoint) and  the probe function fails returning
> -ENODEV.

Right, there is the message.

> Do you see any warning in the logs when you revert the commit? It was
> added to prevent using wrong endpoint types, which will display the
> following warning: "BOGUS urb xfer, pipe "some_number" != type
> "another_number""

The revert was tested on the downstream kernel, but it has also the
check of bogus pipe, and there was no such warning, as far as I see
the report.

> I am just wondering if for some reason the check on interrupt type is
> wrong here.

I'll ask reporters to give the lsusb -v output so that we can take a
deeper look.  Also, I'm building a test kernel based on 6.8-rc7 with
the revert, and ask reporters to test with it, just to be sure.


thanks,

Takashi