[U-Boot] Issue with USB mass storage (thumb drives)

[Marek Vasut]

On 05/04/2016 11:13 AM, Diego wrote:
> In data martedì 3 maggio 2016 23:01:10, Marek Vasut ha scritto:
>> On 04/29/2016 09:58 AM, Diego wrote:
>>> In data venerdì 29 aprile 2016 00:49:22, Marek Vasut ha scritto:
>>>> Urgh, so you seem to have third revision of this stick. I have two
>>>
>>>> sticks which are exactly the same and work in U-Boot on MX6 wandboard:
>>> Hi Marek,
>>>
>>> how big is the file you're trying to load?
>>>
>>> For me it fails for files bigger than 16MB:
>>
>> Ha ok, I see it now. According to the bus analyzer, the stick Acks long
>> block transfer, but then just times out, I guess because it prepares the
>> data or something. Just a dummy question, did you try reducing
>> USB_MAX_XFER_BLK ? Try with 4096 instead of 65536 , that might work.
>>
> 
> Hi Marek,
> 
> that was the original argument of my mail thread:
> http://lists.denx.de/pipermail/u-boot/2016-April/251799.html
> Changing USB_MAX_XFER_BLK from 65535 to 32767 definitely fixed the "EHCI timed 
> out on TD".
> 
> I was questioning what was the best approach to fix the problem.
> It seems that 65536 doesn't work for quite some USB thumb drives. Seeing my 
> experience, my coworker's experience, and previous mails in this same thread, 
> I'd guess something like 50% or lower work with 65535, while something like 
> 90% or more work with 32767.
> http://lists.denx.de/pipermail/u-boot/2016-February/245893.html
> 
> So I see three options:
> 1) 65535 default with quirk table
> 2) 32767 default without quirk table
> 3) 32767 default with quirk table
> 
> Personally I think 3) would be the safest solution, but I think 2) would at 
> least work for most thumb drives.

1) with the quirk table would be the way to go, modern(ish) drives
should work fine with 65535 .

> As the transfer speed wouldn't be affected much for 32767:
> http://lists.denx.de/pipermail/u-boot/2016-February/246267.html
> and as the quirk table for 65535 would grow quite a lot with time, I think.

Yeah, but with old drives only, which I think is soon gonna be moot.

> Bests,
> Diego
> 


-- 
Best regards,
Marek Vasut