Re: [PATCH] phy: core: Add consumer device link support

From: Kishon Vijay Abraham I <kishon@ti.com>
To: Alexandre Torgue <alexandre.torgue@st.com>,
	Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: youling 257 <youling257@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	USB <linux-usb@vger.kernel.org>, <saravanak@google.com>
Subject: Re: [PATCH] phy: core: Add consumer device link support
Date: Mon, 17 Feb 2020 14:10:30 +0530	[thread overview]
Message-ID: <176af3ee-36ce-5ecd-0e9e-ff1c52ea3389@ti.com> (raw)
In-Reply-To: <3afc9783-813c-ab61-b4f4-e925a32df947@st.com>

Hi,

On 17/02/20 2:05 pm, Alexandre Torgue wrote:
> Hi,
> 
> On 2/14/20 7:46 PM, Andy Shevchenko wrote:
>> On Mon, Feb 10, 2020 at 1:32 PM Alexandre Torgue
>> <alexandre.torgue@st.com> wrote:
>>> On 2/10/20 9:08 AM, Kishon Vijay Abraham I wrote:
>>>> On 07/02/20 12:27 PM, youling 257 wrote:
>>>>> test this diff, dwc3 work for my device, thanks.
>>>>>
>>>>> 2020-02-07 13:16 GMT+08:00, Kishon Vijay Abraham I <kishon@ti.com>:
>>>>>> On 06/02/20 7:09 PM, youling257 wrote:
>>>>>>> This patch cause "dwc3 dwc3.3.auto: failed to create device link to
>>>>>>> dwc3.3.auto.ulpi" problem.
>>>>>>> https://bugzilla.kernel.org/show_bug.cgi?id=206435
>>
>> +1 to the report.
>> Please revert for v5.6 or provide a fix ASAP!
>>
> 
> Kishon, do you plan to do the fix? If not, I'll send it quickly.

Please send a fix for it.

Thanks
Kishon

> 
> Thanks
> Alex
> 
>>>>>>
>>>>>> I'm suspecting there is some sort of reverse dependency with dwc3
>>>>>> ULPI.
>>>>>> Can you try the following diff?
>>>>>>
>>>>>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>>>>>> index 2eb28cc2d2dc..397311dcb116 100644
>>>>>> --- a/drivers/phy/phy-core.c
>>>>>> +++ b/drivers/phy/phy-core.c
>>>>>> @@ -687,7 +687,7 @@ struct phy *phy_get(struct device *dev, const
>>>>>> char
>>>>>> *string)
>>>>>>
>>>>>>           get_device(&phy->dev);
>>>>>>
>>>>>> -       link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
>>>>>> +       link = device_link_add(dev, &phy->dev,
>>>>>> DL_FLAG_SYNC_STATE_ONLY);
>>>>>>           if (!link) {
>>>>>>                   dev_err(dev, "failed to create device link to
>>>>>> %s\n",
>>>>>>                           dev_name(phy->dev.parent));
>>>>>> @@ -802,7 +802,7 @@ struct phy *devm_of_phy_get(struct device *dev,
>>>>>> struct device_node *np,
>>>>>>                   return phy;
>>>>>>           }
>>>>>>
>>>>>> -       link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
>>>>>> +       link = device_link_add(dev, &phy->dev,
>>>>>> DL_FLAG_SYNC_STATE_ONLY);
>>>>>>           if (!link) {
>>>>>>                   dev_err(dev, "failed to create device link to
>>>>>> %s\n",
>>>>>>                           dev_name(phy->dev.parent));
>>>>>> @@ -851,7 +851,7 @@ struct phy *devm_of_phy_get_by_index(struct
>>>>>> device
>>>>>> *dev, struct device_node *np,
>>>>>>           *ptr = phy;
>>>>>>           devres_add(dev, ptr);
>>>>>>
>>>>>> -       link = device_link_add(dev, &phy->dev, DL_FLAG_STATELESS);
>>>>>> +       link = device_link_add(dev, &phy->dev,
>>>>>> DL_FLAG_SYNC_STATE_ONLY);
>>>>>>           if (!link) {
>>>>>>                   dev_err(dev, "failed to create device link to
>>>>>> %s\n",
>>>>>>                           dev_name(phy->dev.parent));Parent
>>>>
>>>> Can you check if this doesn't affect the suspend/resume ordering?
>>>
>>> With this fix, suspend/resume ordering is broken on my side. What do you
>>> think to keep the STATELESS flag and to only display a warn if
>>> "device_link_add" returns an error ? It's not "smart" but it could
>>> solved our issue.
>>>
>>> As a lot of improvements have been recently done on device link topic by
>>> Saravana, we could check with him what is the way to follow.
>>>
>>> Regards
>>> Alex
>>>
>>>>
>>>> Thanks
>>>> Kishon
>>>>
>>
>>
>>