[U-Boot] usb: Fail to get descriptor for USB 2.0 device

[DATACOM - Paulo.Zaneti]

On 23/05/2018 20:40, Bin Meng wrote:
> Hi,
>
> On Thu, May 24, 2018 at 4:51 AM, DATACOM - Paulo.Zaneti
> <paulo.zaneti at datacom.com.br> wrote:
>>
>> On 23/05/2018 15:00, Marek Vasut wrote:
>>> On 05/23/2018 07:52 PM, DATACOM - Paulo.Zaneti wrote:
>>>>
>>>> On 23/05/2018 14:43, Marek Vasut wrote:
>>>>> On 05/23/2018 07:37 PM, DATACOM - Paulo.Zaneti wrote:
>>>>>> On 23/05/2018 14:03, Marek Vasut wrote:
>>>>>>> On 05/23/2018 07:00 PM, DATACOM - Paulo.Zaneti wrote:
>>>>>>>> Hi,
>>>>>>> Hi,
>>>>>>>
>>>>>>>> When trying to migrate a board from u-boot version 2016.09 to version
>>>>>>>> 2018.03, I found a problem with a USB 2.0 device which used to work
>>>>>>>> on
>>>>>>>> version 2016.09.
>>>>>>> Does it still happen in u-boot/master ?
>>>>>> Yes, it still happens.
>>>>>>
>>>>>> I just tested it with the following commit:
>>>>>> dca268a .travis.yml: Further optimizations
>>>>>>>> In u-boot version 2016.09 the device appears like this:
>>>>>>>>
>>>>>>>> 2: Mass Storage,  USB Revision 2.0
>>>>>>>>      - SanDisk Cruzer Blade 200443243002FB509E64
>>>>> Let me guess, is this a DWC2-based host ? You didn't mention which SoC
>>>>> or USB controller it is.
>>>>>
>>>>> Cfr https://lists.denx.de/pipermail/u-boot/2016-January/240090.html ,
>>>>> DWC2 has problems with those sandisk sticks.
>>>> No, it is a NXP T1024 SoC.
>>>> Do you think it may be a problem with the SoC or NXP USB host driver ?
>>>>
>>> So that's chipidea ? That one should be reasonably sane.
>> I don't think so. It uses following drivers:
>>    drivers/usb/host/ehci-fsl.c
>>    drivers/usb/host/ehci-hcd.c
>>
>>> Submit the patch you had in mind and let's see what happens.
>> I just noticed that this stick needs more time after the usb_set_address()
>> call.
>> I increased the mdelay(10) to mdelay(20) and the "usb start" command worked.
>> But the problem is that I am still not convinced that this should be the
>> solution.
>>
> Agreed. Can you bisect to see which commit broke your stick?
Yes. The commit which broke my stick is:

commit c008faa77358bb5b313696dd1d5bb8afa03a6ca2
Author: Bin Meng <bmeng.cn at gmail.com>
Date:   Mon Sep 18 06:40:42 2017 -0700

     usb: Only get 64 bytes device descriptor for full speed devices


My first guess was that this commit should be adapted to 
"get_descriptor_len()" for USB_SPEED_HIGH too.

But then, I realized that I can bypass this problem by increasing the 
mdelay() after usb_set_address() from 10 to 20 msec.

So, I think commit c008faa77358bb5b313696dd1d5bb8afa03a6ca2 is not the 
offender one. It probably uncovered another problem with this stick.

I will try to get a better understanding before submitting a patch.
>
> Regards,
> Bin
Thank you guys for all the help. I hope I can contribute back too.

Regards,
Paulo