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Subject: Re: [PATCH 1/1] usb: typec: tcpm: remove unused static variable
 'tcpm_altmode_ops'
To:     Guenter Roeck <linux@roeck-us.net>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Zhen Lei <thunder.leizhen@huawei.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb <linux-usb@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
References: <20210407091540.2815-1-thunder.leizhen@huawei.com>
 <YG6+mfqIc15rc9H1@kuha.fi.intel.com>
 <aa30675b-a487-a605-7dae-4b9c18ad11e0@roeck-us.net>
From:   Hans de Goede <hdegoede@redhat.com>
Message-ID: <8e3ae637-dc52-3285-2862-bee36e1dca14@redhat.com>
Date:   Thu, 8 Apr 2021 19:14:01 +0200
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Precedence: bulk

Hi,

On 4/8/21 3:55 PM, Guenter Roeck wrote:
> On 4/8/21 1:28 AM, Heikki Krogerus wrote:
>> On Wed, Apr 07, 2021 at 05:15:40PM +0800, Zhen Lei wrote:
>>> Fixes the following W=1 kernel build warning:
>>>
>>> drivers/usb/typec/tcpm/tcpm.c:2107:39: warning: ‘tcpm_altmode_ops’ defined but not used [-Wunused-const-variable=]
>>>
>>> The reference to the variable 'tcpm_altmode_ops' is deleted by the
>>> commit a079973f462a ("usb: typec: tcpm: Remove tcpc_config configuration
>>> mechanism").
>>>
>>> By the way, the static functions referenced only by the variable
>>> 'tcpm_altmode_ops' are deleted accordingly.
>>>
>>> Reported-by: Hulk Robot <hulkci@huawei.com>
>>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>>
>> Oh, I thought this was already fixed. Should this go into the stable
>> trees as well?
>>
> 
> I thought there was some code supposed to be coming which would make use of it,
> but my memory may defeat me.

There is code coming which uses this; and this is necessary to make
DP altmode work on some devices.

I have dropped the ball a bit on posting a v2 of my series using this.

I'll prepare a v2 of my series, addressing Heikki's review comments
to my v1 right away. I'll post a v2 at the latest tomorrow.

This is something which is on my TODO list anyways and this way we will
save some churn with these functions going away only to be re-introduced
again relatively soon after they were removed.

Regards,

Hans


> Either case, it is getting old. It it is ever needed,
> it can be reintroduced.
> 
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> 
> Guenter
> 
>> Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
>>
>>> ---
>>>  drivers/usb/typec/tcpm/tcpm.c | 60 -------------------------------------------
>>>  1 file changed, 60 deletions(-)
>>>
>>> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
>>> index ce7af398c7c1c1f..2f89bae29c0c297 100644
>>> --- a/drivers/usb/typec/tcpm/tcpm.c
>>> +++ b/drivers/usb/typec/tcpm/tcpm.c
>>> @@ -1365,14 +1365,6 @@ static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
>>>  	mod_vdm_delayed_work(port, 0);
>>>  }
>>>  
>>> -static void tcpm_queue_vdm_unlocked(struct tcpm_port *port, const u32 header,
>>> -				    const u32 *data, int cnt)
>>> -{
>>> -	mutex_lock(&port->lock);
>>> -	tcpm_queue_vdm(port, header, data, cnt);
>>> -	mutex_unlock(&port->lock);
>>> -}
>>> -
>>>  static void svdm_consume_identity(struct tcpm_port *port, const u32 *p, int cnt)
>>>  {
>>>  	u32 vdo = p[VDO_INDEX_IDH];
>>> @@ -1705,8 +1697,6 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port,
>>>  	 *
>>>  	 * And we also have this ordering:
>>>  	 * 1. alt-mode driver takes the alt-mode's lock
>>> -	 * 2. alt-mode driver calls tcpm_altmode_enter which takes the
>>> -	 *    tcpm port lock
>>>  	 *
>>>  	 * Dropping our lock here avoids this.
>>>  	 */
>>> @@ -2060,56 +2050,6 @@ static int tcpm_validate_caps(struct tcpm_port *port, const u32 *pdo,
>>>  	return 0;
>>>  }
>>>  
>>> -static int tcpm_altmode_enter(struct typec_altmode *altmode, u32 *vdo)
>>> -{
>>> -	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
>>> -	int svdm_version;
>>> -	u32 header;
>>> -
>>> -	svdm_version = typec_get_negotiated_svdm_version(port->typec_port);
>>> -	if (svdm_version < 0)
>>> -		return svdm_version;
>>> -
>>> -	header = VDO(altmode->svid, vdo ? 2 : 1, svdm_version, CMD_ENTER_MODE);
>>> -	header |= VDO_OPOS(altmode->mode);
>>> -
>>> -	tcpm_queue_vdm_unlocked(port, header, vdo, vdo ? 1 : 0);
>>> -	return 0;
>>> -}
>>> -
>>> -static int tcpm_altmode_exit(struct typec_altmode *altmode)
>>> -{
>>> -	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
>>> -	int svdm_version;
>>> -	u32 header;
>>> -
>>> -	svdm_version = typec_get_negotiated_svdm_version(port->typec_port);
>>> -	if (svdm_version < 0)
>>> -		return svdm_version;
>>> -
>>> -	header = VDO(altmode->svid, 1, svdm_version, CMD_EXIT_MODE);
>>> -	header |= VDO_OPOS(altmode->mode);
>>> -
>>> -	tcpm_queue_vdm_unlocked(port, header, NULL, 0);
>>> -	return 0;
>>> -}
>>> -
>>> -static int tcpm_altmode_vdm(struct typec_altmode *altmode,
>>> -			    u32 header, const u32 *data, int count)
>>> -{
>>> -	struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
>>> -
>>> -	tcpm_queue_vdm_unlocked(port, header, data, count - 1);
>>> -
>>> -	return 0;
>>> -}
>>> -
>>> -static const struct typec_altmode_ops tcpm_altmode_ops = {
>>> -	.enter = tcpm_altmode_enter,
>>> -	.exit = tcpm_altmode_exit,
>>> -	.vdm = tcpm_altmode_vdm,
>>> -};
>>> -
>>>  /*
>>>   * PD (data, control) command handling functions
>>>   */
>>> -- 
>>> 1.8.3
>>>
>>
> 
>