Hi, Pawel Laszczak <pawell@xxxxxxxxxxx> writes: >>Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes: >>> On Mon, Apr 26, 2021 at 03:52:46PM +0300, Felipe Balbi wrote: >>>> yeah, this is a requirement by the spec, IIRC. A SetAlt to the same >>>> interface/altSetting means the host wants to reset that altSetting. From >>>> the peripheral point of view that means disabling the endpoints and >>>> reenabling them. >>>> >>>> I'm just not entirely sure if we should do this in u_audio or >>>> f_uac[12].c. Arguably, composite.c could detect this and disable the >>>> altSetting, but that would require a huge refactor on the framework. >>>> >>>> My gut feeling is that for the minimal bug fix, we should patch >>>> f_uac[12].c, but all audio function drivers have the same exact bug, so >>>> I don't know. >>>> >>>> If we follow the "standard" of patching the relevant set_alt functions >>>> in the function drivers, the moment we decide to go for a refactoring, >>>> it'll be easier to see common constructs. >>> >>> FWIW, f_mass_storage.c handles this in its do_set_interface() routine. >>> That routine first deallocates any related request buffers and disables >>> any enabled endpoints in the interface. It then goes on to enable >>> endpoints for the new alternate setting and allocate request buffers. >>> >>> The audio function drivers could follow this approach. >> >>right, that's what all other drivers do, in fact. Only audio seems to be >>different. The question here is whether to patch every f_uac*.c (there >>are three of them) or patch it in the generic u_audio.c >> > > I agree that the best solution is to create common implementation in > composite.c. Maybe usb_function->get_alt and usb-function->set_alt will > be enougt to detect such case from composite.c. The problem can be > with testing such change with all functions. > > For fast fix bug I don't have opinion which place is better u_audio.c or > f_uac*.c. > > First version of this patch makes change only in f_uac2.c and the second > Version moved fix to u_audio.c (as suggested Peter). okay, I missed that Peter had already asked you to move to u_audio.c. I guess we should go with your patch, but it would be nice to get some Tested-bys. Peter, would you be willing to provide some testing for this patch? > Change in u_audio is simpler, and as wrote Felipe is common for all > UAC drivers. Maybe for fast fix it's better. > > If you want, you can feel free to change and modify this patch. heh, that's not how things work around here :-) > It is important for me to fix this issue because it was hard to debug. yup, no question. -- balbi
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