linux-kernel - Re: [PATCH v2 1/2] usb: typec: ucsi: Enable ASUS zenbook quirk for VivoBooks

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Message-ID: <Ztbvw5seWqRA5/8L@kuha.fi.intel.com>
Date: Tue, 3 Sep 2024 14:15:15 +0300
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: "Christian A. Ehrhardt" <lk@...e.de>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	Anurag Bijea <icaliberdev@...il.com>,
	Christian Heusel <christian@...sel.eu>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
	Jameson Thies <jthies@...gle.com>,
	Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Subject: Re: [PATCH v2 1/2] usb: typec: ucsi: Enable ASUS zenbook quirk for
 VivoBooks

On Fri, Aug 30, 2024 at 11:40:07PM +0200, Christian A. Ehrhardt wrote:
> 
> Hi Heikki,
> 
> On Fri, Aug 30, 2024 at 11:12:52AM +0300, Heikki Krogerus wrote:
> > Hi, Christian,
> > 
> > Sorry, I did not look at this properly in v1.
> > 
> > On Thu, Aug 29, 2024 at 12:01:08PM +0200, Christian A. Ehrhardt wrote:
> > > The quirk for some ASUS zenbook models is required for
> > > ASUS VivoBooks. Apply the quirk to these as well.
> > > 
> > > This is part of the fix for the builtin keyboard on ASUS
> > > VivoBooks.
> > 
> > I think that explanation goes to patch 2/2 and vise versa.
> 
> Obviously! Sorry about that.
> 
> > 
> > > Reported-by: Anurag Bijea <icaliberdev@...il.com>
> > > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219108
> > > Bisected-by: Christian Heusel <christian@...sel.eu>
> > > Fixes: de52aca4d9d5 ("usb: typec: ucsi: Never send a lone connector change ack")
> > > Cc: stable@...r.kernel.org
> > > Signed-off-by: Christian A. Ehrhardt <lk@...e.de>
> > > ---
> > >  drivers/usb/typec/ucsi/ucsi.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > > 
> > > diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> > > index 4039851551c1..540cb1d2822c 100644
> > > --- a/drivers/usb/typec/ucsi/ucsi.c
> > > +++ b/drivers/usb/typec/ucsi/ucsi.c
> > > @@ -38,6 +38,10 @@
> > >  
> > >  void ucsi_notify_common(struct ucsi *ucsi, u32 cci)
> > >  {
> > > +	/* Ignore bogus data in CCI if busy indicator is set. */
> > > +	if (cci & UCSI_CCI_BUSY)
> > > +		return;
> > 
> > This does not look correct. Doesn't this mean you'll timeout always if
> > BUSY is set?
> 
> This is only in the notify function that would do the wakeup on
> command completion. The very point of this change is that we do no
> wakeup if UCSI_CCI_BUSY is set along with other bogus bits.
> 
> The UCSI controller is supposed to send another notification without
> the busy bit set once the command completes.
> 
> Note that the ASUS laptop actually sends notifications with the BUSY
> bit set while processing a command. This is presumably to let us know
> that the command is being processed but that it takes longer.
> 
> For example this is a possible sequence:
> ucsi_sync_control_common: cmd=20012	# GET_CONNECT_STATUS
> ucsi_notify_common: cci=0x10000002	# BUSY notification
> ucsi_notify_common: cci=0x80000904	# Command completion
> 
> > Couldn't you just check the BUSY as the first action, and then clear
> > the other bits in CCI if it is set, if that is the problem?
> 
> That would not make any difference. The value is only used in this function
> for a few other checks that look at fields that are supposed to be zero.
> Thus zeroing these fields would have the same effect.
> 
> I think you had the actual error handling in mind that happens _after_
> the timeout hits. CCI is read again there and if it still reports BUSY
> the command is canceled.
> 
> > Btw. Does 4f322657ade1 ("usb: typec: ucsi: Call CANCEL from single
> > location") affect the situation in any way?
> 
> I would have to check with the reporter of the bug but I don't think
> it makes a difference because this is the error recovery code that
> runs after the timeout. I only touched the notification code that would
> do the wakeup.

Okay. Can you resend this with the correct commit message.

thanks,

-- 
heikki