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From: Greg KH <gregkh@linuxfoundation.org>
To: Mark Pearson <mpearson-lenovo@squebb.ca>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: typec: ucsi: Handle incorrect num_connectors capability
Date: Thu, 18 Sep 2025 09:50:30 +0200	[thread overview]
Message-ID: <2025091819-bullion-hut-8242@gregkh> (raw)
In-Reply-To: <1c185541-2b6b-4c43-938a-9f4f4d1499b4@app.fastmail.com>

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 :)

  reply	other threads:[~2025-09-18  7:50 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 [this message]
2025-09-19  7:44         ` Heikki Krogerus
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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