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The following commit(s) were added to refs/heads/master by this push:
new d6444d0a7bd drivers/usbdev: re-assert soft connect in cdcecm/cdcncm
disconnect()
d6444d0a7bd is described below
commit d6444d0a7bd15c266b715e371b0ba520e7a8bc10
Author: Ricard Rosson <[email protected]>
AuthorDate: Wed Jul 29 11:07:18 2026 +0100
drivers/usbdev: re-assert soft connect in cdcecm/cdcncm disconnect()
The USB device controller drivers invoke CLASS_DISCONNECT() on every
USB bus reset, and a bus reset is the first step of normal host
enumeration. Every other class driver (cdcacm, usbmsc, rndis)
re-asserts DEV_CONNECT() at the end of its disconnect() handler so
that the device remains attached; cdcecm and cdcncm did not, so on
controllers that soft-disconnect around bus reset (e.g. rp2040, which
drops the pull-up in its bus-reset handler) a standalone CDC-ECM or
CDC-NCM device is left soft-disconnected by the first bus reset and
never enumerates on the host.
Mirror the cdcacm behavior and perform the soft connect in the
disconnect() methods, unless part of a composite device (composite.c
already re-connects in its own disconnect handler).
Fixes the standalone CDC-ECM case of issue #15880.
Validated on raspberrypi-pico (RP2040): with this change a standalone
CONFIG_NET_CDCECM device that previously never appeared on the host
enumerates via cdc_ether and pings with 0% loss. cdcncm has the
identical defect and receives the identical fix.
Signed-off-by: Ricard Rosson <[email protected]>
Co-authored-by: Xiang Xiao <[email protected]>
Assisted-by: Claude (Anthropic Claude Code)
---
drivers/usbdev/cdcecm.c | 11 +++++++++++
drivers/usbdev/cdcncm.c | 11 +++++++++++
2 files changed, 22 insertions(+)
diff --git a/drivers/usbdev/cdcecm.c b/drivers/usbdev/cdcecm.c
index 2ce7e93cadf..c39f84d4228 100644
--- a/drivers/usbdev/cdcecm.c
+++ b/drivers/usbdev/cdcecm.c
@@ -1916,6 +1916,17 @@ static void cdcecm_disconnect(FAR struct
usbdevclass_driver_s *driver,
FAR struct usbdev_s *dev)
{
uinfo("\n");
+
+ /* Perform the soft connect function so that we will we can be
+ * re-enumerated (unless we are part of a composite device). The USB
+ * device controller calls CLASS_DISCONNECT() on every bus reset, which
+ * is the first step of any enumeration, so without this the device is
+ * left soft-disconnected and never enumerates on the host.
+ */
+
+#ifndef CONFIG_CDCECM_COMPOSITE
+ DEV_CONNECT(dev);
+#endif
}
/****************************************************************************
diff --git a/drivers/usbdev/cdcncm.c b/drivers/usbdev/cdcncm.c
index 7f10e5355e3..c7046c4ca74 100644
--- a/drivers/usbdev/cdcncm.c
+++ b/drivers/usbdev/cdcncm.c
@@ -2902,6 +2902,17 @@ static void cdcncm_disconnect(FAR struct
usbdevclass_driver_s *driver,
cdcncm_resetconfig(self);
uinfo("\n");
+
+ /* Perform the soft connect function so that we can be
+ * re-enumerated (unless we are part of a composite device). The USB
+ * device controller calls CLASS_DISCONNECT() on every bus reset, which
+ * is the first step of any enumeration, so without this the device is
+ * left soft-disconnected and never enumerates on the host.
+ */
+
+#ifndef CONFIG_CDCNCM_COMPOSITE
+ DEV_CONNECT(dev);
+#endif
}
/****************************************************************************
