mkdir acm.${name} in configfs always fails with "Device or resource busy"

mkdir acm.${name} in configfs always fails with "Device or resource busy"

[Sid Spry]

See title. I'm getting this even when using shell commands, so I don't think it is my program.
Creating anything else, like ncm.usb0, will work.

Re: mkdir acm.${name} in configfs always fails with "Device or resource busy"

[Felipe Balbi]

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Hi,

"Sid Spry" <sid@aeam.us> writes:
> See title. I'm getting this even when using shell commands, so I don't
> think it is my program.  Creating anything else, like ncm.usb0, will
> work.

which kernel version? which usb controller? which platform?

-- 
balbi

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Re: mkdir acm.${name} in configfs always fails with "Device or resource busy"

[Sid Spry]

On Mon, Aug 24, 2020, at 1:16 AM, Felipe Balbi wrote:
> 
> Hi,
> 
> "Sid Spry" <sid@aeam.us> writes:
> > See title. I'm getting this even when using shell commands, so I don't
> > think it is my program.  Creating anything else, like ncm.usb0, will
> > work.
> 
> which kernel version? which usb controller? which platform?
> 

Kernel 5.4.45 compiled for a Raspberry Pi 4, the UDC is a DWC2.
Apologies.

On another device (Allwinner based) I could add one serial gadget
but not two, and I though this may have been endpoint exhaustion. Now
I am not so sure.

Re: mkdir acm.${name} in configfs always fails with "Device or resource busy"

[Felipe Balbi]

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"Sid Spry" <sid@aeam.us> writes:

> On Mon, Aug 24, 2020, at 1:16 AM, Felipe Balbi wrote:
>> 
>> Hi,
>> 
>> "Sid Spry" <sid@aeam.us> writes:
>> > See title. I'm getting this even when using shell commands, so I don't
>> > think it is my program.  Creating anything else, like ncm.usb0, will
>> > work.
>> 
>> which kernel version? which usb controller? which platform?
>> 
>
> Kernel 5.4.45 compiled for a Raspberry Pi 4, the UDC is a DWC2.

great. Latest v5.4 stable is v5.4.60. There have been a few fixes in
dwc2 and gadget drivers between .45 and .60. Just to rule out a problem
that was already fixed, could you merge v5.4.60 to your kernel and try
again?

> On another device (Allwinner based) I could add one serial gadget
> but not two, and I though this may have been endpoint exhaustion. Now
> I am not so sure.

It could exhaustion of Interrupt-capable endpoints. It depends on how
the gadget and the UDC were configured.

cheers

-- 
balbi

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Re: mkdir acm.${name} in configfs always fails with "Device or resource busy"

[Sid Spry]

On Tue, Aug 25, 2020, at 12:27 AM, Felipe Balbi wrote:
> "Sid Spry" <sid@aeam.us> writes:
> 
> > On Mon, Aug 24, 2020, at 1:16 AM, Felipe Balbi wrote:
> >> 
> >> Hi,
> >> 
> >> "Sid Spry" <sid@aeam.us> writes:
> >> > See title. I'm getting this even when using shell commands, so I don't
> >> > think it is my program.  Creating anything else, like ncm.usb0, will
> >> > work.
> >> 
> >> which kernel version? which usb controller? which platform?
> >> 
> >
> > Kernel 5.4.45 compiled for a Raspberry Pi 4, the UDC is a DWC2.
> 
> great. Latest v5.4 stable is v5.4.60. There have been a few fixes in
> dwc2 and gadget drivers between .45 and .60. Just to rule out a problem
> that was already fixed, could you merge v5.4.60 to your kernel and try
> again?
> 
> > On another device (Allwinner based) I could add one serial gadget
> > but not two, and I though this may have been endpoint exhaustion. Now
> > I am not so sure.
> 
> It could exhaustion of Interrupt-capable endpoints. It depends on how
> the gadget and the UDC were configured.
> 

Should have been obvious, but yes, this fixes it. Thanks.

In meantime have been finding a bunch of other behavior I can *explain*
but definitely feel is weird, so will try talking about that on list.