Re: [PATCH] usb:cdns3: Fix for CV CH9 running with g_zero driver.

From: Roger Quadros
Date: Wed Oct 09 2019 - 09:51:01 EST


On 09/10/2019 06:58, Pawel Laszczak wrote:


Peter Chen <peter.chen@xxxxxxx> writes:
On 19-10-07 07:39:11, Pawel Laszczak wrote:
Patch fixes issue with Halt Endnpoint Test observed


during using g_zero
driver as DUT. Bug occurred only on some testing board.

g_zero is legacy, please use configfs function source_sink or loopback

We still want fixes for those ;-)

So, if my understanding is correct in new production systems
using legacy gadget drivers is not recommended and we are not going to fix
any more bugs there.

We can't really control who uses what. So we need to support legacy
drivers as well.

The issue detected by using g_zero is a controller driver issue and not an
issue with g_zero itself.


The legacy gadget drivers remains in the kernel only to support the old

So because we introduce new driver we should not worry about legacy
gadget drivers.

Is my understanding correct ?


Endpoint can defer transition to Halted state if endpoint has pending

The implementation of halt handling is a little complicated, you may
consider return -EAGAIN for functional stall through usb_ep_set_halt
from function driver if the requests are pending, it doesn't need to
defer such kinds of functional stall.

-EAGAIN, IIRC is only supposed to be used for IN endpoint stalls.


Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki