HACK: Solve weird problem with lost OUT transfer on ping-pong endpoint

This adds an unconditional endpoint reset procedure to every SET_FEATURE(UnHalt).

It doesn't really make sense that this is required, *particularly* as
we *MUST NOT* set bEndpoint->bank to 0 here.

Without this patch, I'm observing the following problem:

Every first OUT transfer after a SET_INTERFACE + UNHALT on a bulk endpoint
is lost. "lost" means that it completes successfully on the host, can
be seen completing successfully with an ACK on a USB bus analyzer,
but still doesn't show up in the firmware.  No Endpoint Interrupt
is generated.

This can be reproduced by calling libusb_set_interface_alt_setting()
from the host and then submitting a single OUT transfer.

Change-Id: I18ed530e617baddf76e8f9829512443ce2a76e0d
This commit is contained in:
Harald Welte 2020-01-16 23:20:48 +01:00
parent f1a0ed905b
commit 050b9dde68
1 changed files with 4 additions and 0 deletions

View File

@ -1672,6 +1672,10 @@ uint8_t USBD_HAL_Halt(uint8_t bEndpoint, uint8_t ctl)
UDP->UDP_RST_EP |= 1 << bEndpoint;
UDP->UDP_RST_EP &= ~(1 << bEndpoint);
/* This fixes a weird bug with regard to ping-pong OUT endpoints */
UDP->UDP_RST_EP |= 1 << bEndpoint;
UDP->UDP_RST_EP &= ~(1 << bEndpoint);
/* Return Halt status */