[FIX PATCH v1] Fix: common: usb_hub: Reset only USB3.0 hub

Tue Feb 13 00:33:08 CET 2024

On 2/12/24 22:10, Dragan Simic wrote:
> Hello Marek, Andre and Shantur,
> 
> On 2024-02-12 21:19, Marek Vasut wrote:
>> On 2/12/24 14:41, Shantur Rathore wrote:
>>> On Mon, Feb 12, 2024 at 1:40 PM Shantur Rathore <i at shantur.com> wrote:
>>>> On Sat, Feb 10, 2024 at 7:13 AM Dragan Simic <dsimic at manjaro.org> 
>>>> wrote:
>>>>> On 2024-02-08 15:17, Dragan Simic wrote:
>>>>>> On 2024-02-08 15:10, Shantur Rathore wrote:
>>>>>>> On Thu, Feb 8, 2024 at 1:44 PM Dragan Simic <dsimic at manjaro.org>
>>>>>>> wrote:
>>>>>>>> On 2024-02-08 14:33, Marek Vasut wrote:
>>>>>>>>> On 2/8/24 12:30, Shantur Rathore wrote:
>>>>>>>>>> On Wed, Feb 7, 2024 at 1:07 PM Marek Vasut <marex at denx.de> wrote:
>>>>>>>>>>> On 2/7/24 11:23, Shantur Rathore wrote:
>>>>>>>>>>>> USB 3.0 spec requires hub to reset device while
>>>>>>>>>>>> enumeration. Some USB 2.0 hubs / devices don't
>>>>>>>>>>>> handle this well and after implementation of
>>>>>>>>>>>> reset some USB 2.0 disks weren't detected on
>>>>>>>>>>>> Allwinner based boards.
>>>>>>>>>>>>
>>>>>>>>>>>> Resetting only when hub is USB 3.0 fixes it.
>>>>>>>>>>>
>>>>>>>>>>> It would be good to include as many details about the faulty 
>>>>>>>>>>> hardware
>>>>>>>>>>> in
>>>>>>>>>>> the commit message as possible, so that when someone else 
>>>>>>>>>>> runs into
>>>>>>>>>>> this, they would have all that information available.
>>>>>>>>>>>
>>>>>>>>>>>> Tested-by: Andre Przywara <andre.przywara at arm.com>
>>>>>>>>>>>>
>>>>>>>>>>>> Signed-off-by: Shantur Rathore <i at shantur.com>
>>>>>>>>>>>> ---
>>>>>>>>>>>>
>>>>>>>>>>>>     common/usb_hub.c | 6 ++++--
>>>>>>>>>>>>     1 file changed, 4 insertions(+), 2 deletions(-)
>>>>>>>>>>>>
>>>>>>>>>>>> diff --git a/common/usb_hub.c b/common/usb_hub.c
>>>>>>>>>>>> index 3fb7e14d10..2e054eb935 100644
>>>>>>>>>>>> --- a/common/usb_hub.c
>>>>>>>>>>>> +++ b/common/usb_hub.c
>>>>>>>>>>>> @@ -174,8 +174,10 @@ static void usb_hub_power_on(struct
>>>>>>>>>>>> usb_hub_device *hub)
>>>>>>>>>>>>
>>>>>>>>>>>>         debug("enabling power on all ports\n");
>>>>>>>>>>>>         for (i = 0; i < dev->maxchild; i++) {
>>>>>>>>>>>> -             usb_set_port_feature(dev, i + 1, 
>>>>>>>>>>>> USB_PORT_FEAT_RESET);
>>>>>>>>>>>> -             debug("Reset : port %d returns %lX\n", i + 1,
>>>>>>>>>>>> dev->status);
>>>>>>>>>>>> +             if (usb_hub_is_superspeed(dev)) {
>>>>>>>>>>>
>>>>>>>>>>> Should this condition be "all which are lower than superspeed"
>>>>>>>>>>> instead ,
>>>>>>>>>>> so when the next generation of USB comes, this problem won't 
>>>>>>>>>>> trigger
>>>>>>>>>>> ?
>>>>>>>>>>>
>>>>>>>>>>> What does Linux do btw ?
>>>>>>>>>>
>>>>>>>>>> As of now Linux checks if the hub is superspeed
>>>>>>>>>> https://github.com/torvalds/linux/blob/master/drivers/usb/core/hub.c#L2859
>>>>>>>>>>
>>>>>>>>>> which is
>>>>>>>>>>    return hdev->descriptor.bDeviceProtocol == USB_HUB_PR_SS; //
>>>>>>>>>> USB_HUB_PR_SS = 3
>>>>>>>>>>
>>>>>>>>>> This holds true for newer SuperSpeedPlus hubs as well.
>>>>>>>>>> https://github.com/torvalds/linux/blob/master/drivers/usb/core/hub.h#L155
>>>>>>>>>>
>>>>>>>>>> We can change the check to be  bDeviceProtocol > 2 but who 
>>>>>>>>>> knows if
>>>>>>>>>> things change in the newer version of spec.
>>>>>>>>>> I am open to suggestions.
>>>>>>>>>
>>>>>>>>> Please just include the ^ in the commit description. Use link to
>>>>>>>>> git.kernel.org , not some mirror . This is extremely useful
>>>>>>>>> information and, well, you already wrote the V2 commit message
>>>>>>>>> addition in this answer.
>>>>>>>>
>>>>>>>> Shantur, if that would be easier or quicker for you, I can write
>>>>>>>> a quite detailed patch description for you, in exchange for a
>>>>>>>> "Helped-by" tag in the v2 patch submission. :)
>>>>>>>
>>>>>>> That would be really kind of you Dragan.
>>>>>>
>>>>>> Sure, I'll write the summary and send it over.
>>>>>>
>>>>>>> I am down with the flu so that would really help me as my brain is
>>>>>>> working at 15% capacity.
>>>>>>
>>>>>> Oh, I'm really sorry to hear that. :(  I hope you'll get better
>>>>>> soon, and I know very well what's it like;  I've also been sick
>>>>>> recently, as a result of some kind of flu that unfortunately found
>>>>>> its way into my lungs, and it took me about a month to get back
>>>>>> to about 90% of my usual mental capacity.  I'm still not back to
>>>>>> exactly 100%. :/
>>>>>>
>>>>>> I really hope you'll recover much faster.
>>>>>
>>>>> I hope you're feeling better.
>>>>>
>>>>> Below are the patch subject and description that I prepared for you,
>>>>> please have a look.
>>>>>
>>>>> ------- >8 ------------- >8 ------------- >8 ------------- >8 -------
>>>>> [PATCH v2] common: usb-hub: Reset USB 3.0 hubs only
>>>>>
>>>>> Additional testing of the changes introduced in commit 33e06dcbe57a
>>>>> ("common:
>>>>> usb-hub: Reset hub port before scanning") revealed that some USB 3.0
>>>>> flash
>>>>
>>>> I think it was a USB 2.0 drive that didn't work on the USB 2.0 port.
>>>>
>>>>> drives didn't work in U-Boot on some Allwinner SoCs that support 
>>>>> USB 2.0
>>>>> only.
>>>>> More precisely, some tested USB 3.0 flash drives failed to be detected
>>>>> and
>>>>> work on an OrangePi Zero 3 with Allwinner H616 SoC, which supports USB
>>>>> 2.0
>>>>> only, while the same USB flash drives worked just fine on a Pine64 H64
>>>>> with
>>>>> Allwinner H6 SoC, which supports both USB 2.0 and 3.0.
>>>>>
>>>>> Resetting USB 3.0 hubs only has been tested to work as expected,
>>>>> resolving
>>>>> the previous issues on the Allwinner H616, while not introducing 
>>>>> any new
>>>>> issues on other Allwinner SoCs.  Thus, let's fix it that way.
>>>>>
>>>>> According to the USB 3.0 specification, resetting a USB 3.0 port is
>>>>> required
>>>>> when an attached USB device transitions between different states, such
>>>>> as
>>>>> when it resumes from suspend.  Though, the Linux kernel performs
>>>>> additional
>>>>> USB 3.0 port resets upon initial USB device attachment, presumably to
>>>>> ensure
>>>>> proper state of the USB 3.0 hub port and proper USB mode negotiation
>>>>> during
>>>>> the initial USB device attachment and enumeration.
>>>>>
>>>>> Such USB port resets don't seem to exist for USB 2.0 hubs, 
>>>>> according the
>>>>> USB
>>>>> 2.0 specification.  The resets seem to be added to the USB 3.0
>>>>> specification
>>>>> as part of the port and device mode negotiation.
>>>>>
>>>>> The Linux kernel also resets USB 3.0 (i.e. SuperSpeed) hubs only, as
>>>>> visible
>>>>> in file drivers/usb/core/hub.c in the kernel source, line 2859. This
>>>>> check
>>>>> also applies to newer SuperSpeed Plus (USB 3.1 or 3.2) hubs as well,
>>>>> which
>>>>> hopefully makes it future proof.
>>>>>
>>>>> Fixes: 33e06dcbe57a ("common: usb-hub: Reset hub port before 
>>>>> scanning")
>>>>> Link:
>>>>> https://lore.kernel.org/u-boot/20240207102327.35125-1-i@shantur.com/T/#u
>>>>> Link:
>>>>> https://lore.kernel.org/u-boot/20240201164604.13315fa6@donnerap.manchester.arm.com/T/#u
>>>>> Signed-off-by: Shantur Rathore <i at shantur.com>
>>>>> Helped-by: Dragan Simic <dsimic at manjaro.org>
>>>>> Tested-by: Andre Przywara <andre.przywara at arm.com>
>>>>> Reviewed-by: Dragan Simic <dsimic at manjaro.org>
>>>>> ------- >8 ------------- >8 ------------- >8 ------------- >8 -------
>>>>
>>>> Regards,
>>>> Shantur
>>>
>>> Is this description acceptable to you Marek.
>>
>> Please send a V2 patch . If possible, include the device information
>> as reported by Andre, esp. which USB stick triggered it, including USB
>> IDs, this is important for future reference and in case someone has
>> similar failure.
> 
> If Andre can supply the USB IDs, I'm willing to help Shantur by
> adjusting the wording of the patch description to include them.

That's what I'm hoping is gonna happen , thanks !

>> Please don't use "in the kernel source, line 2859", considering the
>> rate of change of the Linux kernel, it is best to also include exact
>> commit ID as of which this is a line 2859 and spell out this is
>> referring to Linux kernel.
> 
> Good point.  I'm willing to adjust the wording.

Thanks .