On 8/20/2015 10:45 AM, Felipe Balbi wrote:
> Hi,
>
> On Thu, Aug 20, 2015 at 07:16:48PM +0200, Robert Baldyga wrote:
>> On 08/20/2015 06:48 PM, Felipe Balbi wrote:
>>> On Thu, Aug 20, 2015 at 06:28:14PM +0200, Robert Baldyga wrote:
>>>> Hi Felipe,
>>>>
>>>> On 08/20/2015 05:35 PM, Felipe Balbi wrote:
>>>> [...]
>>>>> just letting you know that this regresses all gadget drivers making them
>>>>> try to disable previously disabled endpoints and enable previously
>>>>> enabled endpoints.
>>>>>
>>>>> I have a possible fix (see below) but then it shows a problem on the
>>>>> host side when using with g_zero (see further below):
>>>>>
>>>>> commit 3b8932100aacb6cfbffe288ca93025d8b8430c00
>>>>> Author: Felipe Balbi <balbi@xxxxxx>
>>>>> Date: Wed Aug 19 18:05:27 2015 -0500
>>>>>
>>>>> usb: gadget: fix ep->claimed lifetime
>>>>>
>>>>> In order to fix a regression introduced by commit
>>>>> cc476b42a39d ("usb: gadget: encapsulate endpoint
>>>>> claiming mechanism") we have to introduce a simple
>>>>> helper to check if a particular is enabled or not.
>>>>>
>>>>> After that, we need to move ep->claimed lifetime to
>>>>> usb_ep_enable() and usb_ep_disable() since those
>>>>> are the only functions which actually enable and
>>>>> disable endpoints.
>>>>>
>>>>> A follow-up patch will come to drop all driver_data
>>>>> checks from function drivers, since those are, now,
>>>>> pointless.
>>>>>
>>>>> Fixes: cc476b42a39d ("usb: gadget: encapsulate endpoint
>>>>> claiming mechanism")
>>>>> Cc: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
>>>>> Signed-off-by: Felipe Balbi <balbi@xxxxxx>
>>>>>
>>>>> diff --git a/drivers/usb/gadget/epautoconf.c b/drivers/usb/gadget/epautoconf.c
>>>>> index 978435a51038..ad45070cd76f 100644
>>>>> --- a/drivers/usb/gadget/epautoconf.c
>>>>> +++ b/drivers/usb/gadget/epautoconf.c
>>>>> @@ -126,7 +126,6 @@ found_ep:
>>>>> ep->address = desc->bEndpointAddress;
>>>>> ep->desc = NULL;
>>>>> ep->comp_desc = NULL;
>>>>> - ep->claimed = true;
>>>>
>>>> Removing this line causes autoconfig can return the same endpoint many
>>>> times. This probably causes problems with g_zero.
>>>>
>>>> I will try to fix it ASAP.
>>>
>>> I was considering the same thing, but the lifetime of ->claimed doesn't
>>> look correct to me either way. Note that once the flag is enabled, it
>>> won't get disabled by most gadget drivers.
>>
>> And it should not be. This flag is indicator, that endpoint is used by some
>> function. It should be set once by usb_ep_autoconfig() and cleared by
>> usb_ep_autoconfig_reset().
And the 'claimed' flag should be used for the ep autoconfig
mechanism alone. We may want to reset it during the autoconfig
phase for multiple configs and alt-interfaces. So there should be
separate 'claimed' and 'enabled' flags.
>
> have you considered switching interfaces and/or alternate settings ?
We ran into similar issues before with this very scenario. Handling
of set_config(0 or N), in both addressed and configured states, and
set_interface requests.
John
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