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From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Mark Pearson <mpearson-lenovo@squebb.ca>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: typec: ucsi: Handle incorrect num_connectors capability
Date: Fri, 19 Sep 2025 10:44:26 +0300	[thread overview]
Message-ID: <aM0J2hDgqkxioAXU@kuha.fi.intel.com> (raw)
In-Reply-To: <2025091819-bullion-hut-8242@gregkh>

On Thu, Sep 18, 2025 at 09:50:30AM +0200, Greg KH wrote:
> On Wed, Sep 17, 2025 at 02:14:28PM -0400, Mark Pearson wrote:
> > Hi all,
> > 
> > On Fri, Aug 22, 2025, at 8:54 AM, Mark Pearson wrote:
> > > Hi Greg,
> > >
> > > On Fri, Aug 22, 2025, at 12:51 AM, Greg KH wrote:
> > >> On Thu, Aug 21, 2025 at 02:53:07PM -0400, Mark Pearson wrote:
> > >>> The UCSI spec states that the num_connectors field is 7 bits, and the
> > >>> 8th bit is reserved and should be set to zero.
> > >>> Some buggy FW has been known to set this bit, and it can lead to a
> > >>> system not booting.
> > >>> Flag that the FW is not behaving correctly, and auto-fix the value
> > >>> so that the system boots correctly.
> > >>> 
> > >>> Found on Lenovo P1 G8 during Linux enablement program. The FW will
> > >>> be fixed, but seemed worth addressing in case it hit platforms that
> > >>> aren't officially Linux supported.
> > >>> 
> > >>> Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca>
> > >>
> > >> Any hints as to what commit id this fixes?
> > >>
> > >> thanks,
> > >>
> > >> greg k-h
> > >
> > > Maybe 3cf657f ('Remove all bit-fields')?
> > >
> > > The commit there states that 'We can't use bit fields with data that is 
> > > received or send
> > > to/from the device.'
> > > Not sure why that is, but I assumed this means we shouldn't change the 
> > > structure to use 7 bits for num_connectors, which was my original plan.
> > >
> > > After that, we go all the way back to the file creation (c1b0bc2) where 
> > > it was defined as 8 bit.
> > >
> > 
> > Just a gentle nudge to see if there are any concerns or questions with the patch.
> 
> I was waiting for the maintainer of this code to review it :)

So not Fixes tag?

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

-- 
heikki

  reply	other threads:[~2025-09-19  7:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-21 18:53 [PATCH] usb: typec: ucsi: Handle incorrect num_connectors capability Mark Pearson
2025-08-22  4:51 ` Greg KH
2025-08-22 12:54   ` Mark Pearson
2025-09-17 18:14     ` Mark Pearson
2025-09-18  7:50       ` Greg KH
2025-09-19  7:44         ` Heikki Krogerus [this message]
2025-09-19 15:45           ` Mark Pearson
2025-09-22 12:48             ` Heikki Krogerus
2025-09-29 19:25               ` Mark Pearson
2025-09-29 19:35                 ` Greg KH
2025-09-29 20:01                   ` Mark Pearson

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