linux-kernel - Re: [PATCH] usb: typec: tcpm: Raise vdm_sm_running flag only when VDM SM is running

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Date:   Thu, 26 Aug 2021 13:48:45 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Kyle Tso <kyletso@...gle.com>
Cc:     linux@...ck-us.net, heikki.krogerus@...ux.intel.com,
        badhri@...gle.com, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] usb: typec: tcpm: Raise vdm_sm_running flag only when
 VDM SM is running

On Mon, Aug 16, 2021 at 03:54:49PM +0800, Kyle Tso wrote:
> If the port is going to send Discover_Identity Message, vdm_sm_running
> flag was intentionally set before entering Ready States in order to
> avoid the conflict because the port and the port partner might start
> AMS at almost the same time after entering Ready States.
> 
> However, the original design has a problem. When the port is doing
> DR_SWAP from Device to Host, it raises the flag. Later in the
> tcpm_send_discover_work, the flag blocks the procedure of sending the
> Discover_Identity and it might never be cleared until disconnection.
> 
> Since there exists another flag send_discover representing that the port
> is going to send Discover_Identity or not, it is enough to use that flag
> to prevent the conflict. Also change the timing of the set/clear of
> vdm_sm_running to indicate whether the VDM SM is actually running or
> not.
> 
> Fixes: c34e85fa69b9 ("usb: typec: tcpm: Send DISCOVER_IDENTITY from dedicated work")
> Cc: Badhri Jagan Sridharan <badhri@...gle.com>
> Signed-off-by: Kyle Tso <kyletso@...gle.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 81 ++++++++++++++++-------------------
>  1 file changed, 38 insertions(+), 43 deletions(-)

This does not apply to my usb-linus branch :(

Please rebase and resend, collecting the acks that others have done.

thanks,

greg k-h