[U-Boot] [PATCH] usb: ci_udc: fix interaction with CONFIG_USB_ETH_CDC

Stephen Warren
2014-06-30T16:02:00Z

On 06/27/2014 07:34 PM, J?rg Krause wrote:
>
> On 06/28/2014 01:37 AM, Stephen Warren wrote:
>> On 06/27/2014 05:16 PM, J?rg Krause wrote:
>>> On 06/27/2014 11:55 PM, Stephen Warren wrote:
>>>> On 06/27/2014 03:37 PM, J?rg Krause wrote:
>>>>> I added the last series of patches beginning from 2014-06-10 for
>>>>> testing
>>>>> purposes. The patches from 2014-05-29 were already applied.
>>>>>
>>>>> First series of patches:
>>>>>
>>>>> Applying: usb: ci_udc: call udc_disconnect() from ci_pullup()
>>>>> Applying: usb: ci_udc: fix freeing of ep0 req
>>>>> Applying: usb: ci_udc: fix probe error cleanup
>>>>> Applying: usb: ci_udc: clean up all allocations in unregister
>>>>>
>>>>> Calling tftp the first time after a reset runs fine,
>>>> I thought the issue you reported was that the *first* time you run the
>>>> "tftp" command, it has issues such as timeouts? Did I misunderstand, or
>>>> did that issue somehow go away?
>>> That's right! This was the state before applying a series of patches
>>> after allow multiple buffer allocs per ep. Now, the first run of tftp
>>> runs without any errors.
>> Just to make sure I understand, here's what you saw:
>>
>> 1) tftp works fine to start with. No timeouts even on repeated
>> invocation.
> I went back in time and now I can be more precise. Everything worked
> fine until commit usb: ci_udc: allow multiple buffer allocs per ep which
> introduces timeouts in almost all tftp file downloads. Even the first
> run of tfpt can end in a timeout.
>
>>
>> 2) You applied "allow multiple buffer allocs per ep"
> Setting #define CONFIG_SYS_CACHELINE_SIZE 32 to my config file helped
> here. But still timeouts. First run almost always runs fine, only
> sometimes timeouts while receiving a packet, but always running to the
> end. Running tftp after this a second time and more fails with a ERROR:
> The remote end did not respond in time. at
> drivers/usb/gadget/ether.c:2388/usb_eth_init(), but sometimes it works.
>
> Setting CONFIG_SYS_CACHELINE_SIZE 32 does not make it better (as I
> previously wrote it).
>
> Removing CONFIG_USB_GADGET_DUALSPEED helps a little bit, but I am
> getting also errors after the second or third run.

Sigh. There's been a lot of flip-flopping re: whether the cacheline size
affects the issue or not, and whether the first TFTP download always
works fine, or whether only the 3rd fails. This makes it very hard for
me to understand the issue that you're seeing. For instance, if even the
first TFTP download can fail (even if intermittently), then there's
clearly a problem with basic driver operation. However, if only the 2nd
or 3rd TFTP ever fails, then the problem is likely isolated to some part
of the cleanup/shutdown code. Given that your reports of the problem
keep flip-flopping about, it makes it hard to decide which part of the
code to look at.

For now, I'm going to simply assume that any TFTP download (1st, 2nd, or
100th) can fail intermittently, and that cache line size is irrelevant.

I'll look at the problematic commit you mentioned (2813006fecda "usb:
ci_udc: allow multiple buffer allocs per ep") and see if I can create a
series of patches that do the same thing, and have you bisect that. If I
can do that, I will ask you to test 100 times each: the commit before
the bad commit, then each of the commits in my series, always resetting
the board between each test and doing a single TFTP download. Then I'd
like to see the raw results from those tests.